Volkswagen Passat B3

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. 25 Continuous Injection System (CIS) (Page GR-25)

Continuous Injection SystemCIS ECM Intake air system Component layout Throttle body Technical dataIgnition timing, idle, co Oxy. sensor, checking Accel./decel fuel shut-off Speedometer speed signal, checking Coolant temperature sensor, checking Cold start valve, checking Air flow sensor, checking and adjusting Air flow sensor potentiometer, checking and adjustingFuel pressure, checkingInjection quantity comparative measurement Idle and full throttle switches, checking and adjustingIntake air preheating, checking

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. CIS-E-Motronic system, component locations (Page 25-10-1)

1 - Harness connector for Oxygen sensor (G 39) up to 7-90, as shown after 8-90, 4-pin harness connector for Oxygen sensor (G 39)* and Oxygen sensor

heater (Z 19) mounted on right engine mount

2 - Throttle body Types: vehicles with separate idle switch (F 60)* and full throttle switch (F 81)* vehicles with integrated idle switch (F 60)*, full throttle switch (F 81)* and throttle

potentiometer3 - CIS-E Motronic control unit (J 204)*4 - Intake air temperature sensor (G 72)5 - EGR valve (exhaust gas recirculation)

California only only function: monitoring the EGR system

6 - CO tap tube7 - Idle stabilizer valve (N 71)**8 - Ignition coil power output stage (N 70)

checking, see Repair Group 289 - Ignition coil (N)

checking, see Repair Group 2810 - 6-pin harness connector11 - Ignition distributor

with Hall sender (G 40)*

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. CIS-E-Motronic system, component locations (Page 25-10-2)

12 - Vacuum amplifier for EGR system (California)

13 - Ignition timing sender (G 4)* on cylinder number 4 ignition wire installed position: tabs must point toward ignition distributor

14 - Thermopneumatic valve on coolant pipe for EGR system (California)

15 - Coolant temperature sensor (G 62)* for CIS-E Motronic system

16 - Cold start valve (N 17)**17 - Knock sensor I (G 61)*18 - Fuel injector(s)19 - Knock sensor II (G 66)*20 - Control flap for intake air pre-heating21 - Differential pressure regulator (N 73)**22 - Fuel distributor23 - Carbon canister

carbon canister system repairing, see Repair Group 2024 - Air filter25 - Air flow sensor potentiometer (G 19)*26 - Fuel pressure regulator27 - Air flow sensor28 - Solenoid valve I (N 80)**

Solenoid valve II (N 115) for carbon canister, see Repair Group 20

29 - Spark plug(s) 25 NM (18 ft lb) specifications and types, see Repair Group 28

30 - Harness connector for idle switch (F60)* and full throttle switch (F 81)** checked using self-diagnosis, see Repair Group D2** checked using output checks, see Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Fuel injection system, repairing (Page 25-20-1)

A - Section 25-50B - Section 25-50C - Section 25-501 - 10 Nm (7 ft lb)2 - 20 Nm (15 ft lb)3 - Fuel return line

blue to pump reservoir, see Repair Group 20

4 - Fuel supply line black from pressure reservoir, see Repair Group 20

5 - Bracket mounted on air flow sensor, see section 25-40 item 8

6 - 3.5 Nm (31 in. lb)7 - Pressure regulator

system, differential and residual pressure checking, see section 25-1908 - Differential pressure regulator harness connector

gray10 - Pressure regulator (N 73)**

differential pressure checking, see section 25-190 resistance: 15 to 25 Ohms

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Fuel injection system, repairing (Page 25-20-2)

11 - O-ring always replace

12 - Control plunger sensor plate lever and control plunger checking, see section 25-170 control plunger removing and installing, see section 25-170

13 - Sealing ring smaller diameter toward control plunger seals sensor plate only when in rest position

14 - Stop screw for control plunger free play adjustment at fuel distributor, see section 25-170

15 - 20 Nm (15 ft lb) if there are engine running disturbances, replace mini-filter with banjo bolt

16 - Fuel distributor injection quantity comparative measurement checking, see section 25-200 after installing fuel distributor, check sensor plate free play and adjust if necessary, see

section 25-17017 - Cap screw

10 Nm (7 ft lb) connection for pressure measuring gauge

**checked using output checks, see Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. CIS-E Motronic control unit, component layout (Page 25-30-1)

1 - Ground connection fastened to Oxygen sensor harness connector bracket

2 - Harness connector for Oxygen sensor (G 39) and sensor heater (Z 19) starting 8-90, 4-pin harness connector mounted on right engine mount check voltage supply for Oxygen sensor heater with engine running, between terminals

1 (brown) and 2 (red/white): must be approx. battery voltage check Oxygen sensor heater for continuity via OXS harness connector (white wires)

3 - Oxygen sensor (G 39) harness connector up to 7-90, single pin harness connector mounted on right firewall

4 - Oxygen sensor heater (Z 19) harness connector up to 7-90, 2-pin harness connector mounted on right firewall check voltage supply for Oxygen sensor heater with engine running, must be approx.

battery voltage check Oxygen sensor heater for continuity via OXS harness connector (white wires)

5 - Harness connector only disconnect or connect harness connector with ignition switched off to disconnect, release holding spring from CIS-E Motronic control unit CIS-E Motronic system electrical checking, see Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. CIS-E Motronic control unit, component layout (Page 25-30-2)

6 - CIS-E Motronic control unit (J 204)* for fuel injection, Oxygen sensor control, ignition map, knock regulation and output

checks with Fault memory for output checks and self-diagnosis, see Repair Group D2

7 - Mounting plate8 - 10 Nm (7 ft lb)9 - A/C harness connector

in right side of plenum10 - Oxygen sensor (G 39)*

50 Nm (37 ft lb) installation location: catalytic converter coat threads with G5 but do not allow compound to enter sensor body slots checking see section 25-100

*check using self-diagnosis, see Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Intake air system, component layout (Page 25-40-1)

C - Section 25-20D - Section 25-50E - Section 25-50F - Section 25-501 - From carbon canister

carbon canister system, repairing, see Repair Group 202 - Harness connector

gray3 - Carbon canister solenoid valve I (N 80)**

gray resistance 30 to 60 Ohms

4 - Carbon canister solenoid valve II (N 115) black checking, see Repair Group 20

5 - Harness connector black

6 - 3.5 Nm (31 in. lb)7 - Mounting bracket8 - Mounting bracket

for fuel pressure regulator, see section 25-20 item 5

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Intake air system, component layout (Page 25-40-2)

9 - Air flow sensor sensor plate lever and control plunger checking, see section 25-170 sensor plate rest position and free play, checking and adjusting, see section 25-170 air flow sensor potentiometer (G 19)*; checking, see section 25-180

10 - Gasket always replace

11 - Warm air intake hose to heat shield from exhaust manifold

12 - Adaptor tube13 - Control flap

intake air pre-heating checking, see section 25-220 not available as an individual part

14 - Air filter housing lower section15 - Cold air intake16 - Air filter element17 - Air filter housing upper section18 - Harness connector

white19 - CO adjustment plug

CO adjusting screw underneath CO content and idle speed checking and adjusting, see section 25-90

20 - Intake air boot

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Fuel injection components, layout (Page 25-50-1)

A - See section 25-20B - See section 25-20D - See section 25-40E - See section 25-40F - See section 25-401 - Connecting tube2 - Temperature controller

intake air pre-heating checking, see section 25-220 installation position: brass connector nipple with notch toward control flap see section

25-40 item 133 - Intake air boot4 - Throttle body assembly

with idle* and full throttle* switch disassembling and reassembling, see section 25-60

5 - 20 Nm6 - Gasket

always replace7 - Intake manifold upper section

first fasten to lower section then mount on rear brackets8 - Bracket

for fuel injector lines and ignition wiring guide

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Fuel injection components, layout (Page 25-50-2)

9 - CO tap tube CO content and idle speed checking and adjusting, see section 25-90

10 - Cap if removed; ensure that re-installation is tight

11 - Check valve for vehicles without ABS only note installed position: arrow on valve points toward intake manifold

12 - From multifunction indicator (A/C) for vehicles without ABS only vacuum connections, see section 25-230

13 - From brake booster for vehicles without ABS only

15 - Ground connection16 - Harness connector

white17 - Coolant temperature sensor (G 62)*

for CIS-E Motronic system checking, see section 25-150 for sensor resistance see chart in Technical data section 25-70

18 - Harness connector gray

19 - Idle stabilizer valve (N 17)** resistance 4 to 12 Ohms

20 - 10 Nm (7 ft lb)21 - Cold start valve (N 17)**

injection pattern, injection time and leak testing, see section 25-160 resistance 8 to 13 Ohms

22 - Harness connector blue

23 - Hose connector24 - Calibrated insert

red25 - From crankcase breather ventilation housing26 - Fuel injector insert

install upper part with D6 locking compound 20 Nm (15 ft lb) remove and install using 3135

27 - O-rings always replace moisten with fuel before installing

28 - Fuel Injector(s) air shrouded injection quantity comparative measurement checking, see section 25-200 check pressure using VAG 1349 injector tester; must be 3.7 to 4.8 bar

29 - Calibrated insert blue

30 - Intake manifold lower section31 - Locking clip

*checked using self-diagnosis, see Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Throttle body, disassembling and reassembling (Page 25-60-1)

1 - Throttle body if stop screw blocked, replace throttle body

2 - Gasket always replace

3 - Full throttle switch (F 81)* checking and adjusting, see section 25-210 for vehicles built after 10-90 starting with control unit: 49 States: 8A0 907 404 California: 893 907 404Q full throttle switch functional testing, see section 25-210

4 - Harness connector to CIS-E Motronic control unit (J 204)*

5 - Harness connector for vehicles with automatic transmission only to automatic transmission control unit

6 - Throttle body idle* and full throttle* switches are contained in an assembly with the throttle

potentiometer if stop screw is blocked; replace throttle body

7 - Heat shield

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Throttle body, disassembling and reassembling (Page 25-60-2)

8 - Throttle potentiometer with integrated idle switch (F 60)* and full throttle switch (F 81)* checking and adjusting, see section 25-210 vehicles built starting 10-90 starting with control unit: 49 States: 8A0 907 404 California: 893 907 404Q

9 - Screw must be turned in all the way idle speed CANNOT be adjusted

10 - Idle switch (F 60)* checking and adjusting, see section 25-210 for vehicles built after 10-90 starting with control unit: 49 States: 8A0 907 404 California: 893 907 404Q

*checked by self-diagnosis - Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Technical Data (Page 25-70-1)

Engine code 9ACIS-E Motronic control unit RPM cut-off to 9-90 approx. 6800 RPM

Fuel shut off by control current reversal at pressure regulator after 10-90 approx. 7000 RPM

Ignition timing Checking value See Repair Group 28 for additional information

4-8 BTDC

speed* Checking value to 9-90CANNOT be adjusted; controlled by idle stabilization system after 10-90

700-900 RPM 800-1000 RPM

CO content* Checking value Measured at CO tap tube Adjusting value (via pressure regulator control current adjustment) *Note checking/adjusting conditions section 25-90

0.2 to 1.2 volume %

2.5 2.5 mA (must fluctuate)

Fuel pressure System pressure Differential pressure Differential pressure regulator harness connector disconnected Differential pressure regulator for harness connector connected Residual pressure After minimum of 10 minutes After minimum of 20 minutes

6.1-6.6 bar

approx. 0.3 to 0.5 bar below system pressure approx. 1.3 to 1.6 bar

below system pressure

3.3 bar 3.2 bar

Fuel injectors Spray pressure Injection quantity tolerance within a set: Idle measurement (1st detent) with a 20 ml accumulation Full throttle measurement (2nd detent) with 80 ml accumulation

3.7 to 4.8 bar

2.0 ml maximum

8.0 ml maximum

Idle stabilizer valve resistance 4 to 12 Ohms

Pressure regulator resistance 15 to 25 Ohms

Cold start valve resistance 8 to 13 Ohms

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Technical Data (Page 25-70-2)

Engine code 9A

Idle switch, switching point Using feeler gauge; measure gap between activating lever and throttle lever or between throttle lever and idle stop

0.15 to 0.50 mm before full throttle stop

Full load switch, switching point Measured using 3084 protractor and adaptor 3084/1

10 2 before full throttle stop

Coolant temperature sensor (G 62) resistance

NoteResistance is dependent on coolant temperature.

If resistance measurement is acceptable but Repair Group D2 is still displayed via self-diagnosis, it is possible that there is an intermittent signal. If this is the case, perform Electrical Test step 23 in Repair Group D2.For vehicles build after 10-90 starting with control unit:

49 States: 8A0 907 404 California: 893 907 404Q

The sensor can also be checked using the VAG 1551 Diagnostic Tester, see section 25-150.

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Safety precautions (Page 25-80-1)

Rules of CleanlinessCAUTION!When working on the fuel supply/injection system, carefully observe the following rules:1 - thoroughly clean connection and surrounding areas before loosening

connection2 - after removing components, place in clean area and cover with foil or paper,

avoid using rags3 - components which have been opened or disassembled must be carefully

covered or sealed if repair cannot be carried out immediately4 - install clean parts only

remove replacement parts from package just before installing

do NOT use spare parts that were stored loose or unpackaged (e.g. in tool boxes, etc.)

5 - when fuel system is open: avoid using compressed air whenever possible avoid moving the vehicle whenever possibleSafety measuresWARNING!Fire Hazard! Do not smoke or have anything in area that can ignite fuel.

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Safety precautions (Page 25-80-2)

CAUTION!Observe the following precautions to prevent personal injury as well as possible damage to sensitive electrical components.

switch OFF the ignition before connecting or disconnecting components or test equipmentconnect and disconnect battery ONLY with ignition switched OFF otherwise the control unit could be damagedif the engine must be cranked but not started (for compression testing etc.) disconnect Hall sender harness connector at ignition distributor

NoteA variety of electrical connectors are used on this vehicle, ALWAYS use the VW 1594 adaptor kit to connect test instruments to these connectors.CAUTION!Before disconnecting a customers battery; ALWAYS ask for the radio code (if equipped with an anti-theft radio).

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Ignition timing, idle speed and CO content, checking/adjusting (Page 25-90-1)

Checking conditions:engine coolant temperature 80 C (176 F) minimumall electrical consumers switched OFFradiator cooling fan must not be running while taking measurementsA/C switched OFFFault memory must be clear of stored faults, if any are found they must be corrected and then Fault memory erased before proceedingno pressure measuring equipment connectedif injector lines were loosened or replaced, run engine up to 3000 RPM several times and then allow to idle for at least 2 minutes before performing the adjustment any adjustmentsexhaust must be leak-freethrottle cable adjustment OK, see Repair Group 20

Vehicles with automatic transmission:set selector lever in P or N position

Vehicles built up to 9-90:switch OFF ignition

connect VAG 1367 engine tester using VAG 1367/8 inductive pickup


connect Sun EPA 75 (or EPA approved equivalent) CO tester using VAG 1363/3 adaptor connected to CO tap tube

CAUTION!Adaptor must be connected tightly to CO tap tube to prevent measuring errors.

start engine and let idlecheck ignition timing

checking value 4 to 8 BTDCIf adjustment is necessary see Repair Group 28 for additional information

check idle speed (CANNOT be adjusted)must be 700 to 900 RPM

NoteIf RPM is held at a constant 700 RPM, perform Electrical Test Steps 5 and/or 6 in Repair Group D2.

check CO contentmust be 0.2 to 1.2 volume %

If NO, adjust CO as follows:switch OFF ignition

disconnect harness connector 1 from carbon canister solenoid valve 2 (black)


disconnect crankcase housing breather hoses 1 and 2 from breather housing 3 and place hoses such that only fresh air can be drawn in

calibrated insert 4 must remain in hose 2ensure that ignition is switched OFFdisconnect harness connector from differential pressure regulator 1connect test adaptor VAG 1315A/1 between differential pressure regulator and harness connector (arrows)switch Fluke 83 multimeter to 200 mA range

connect multimeter to test adaptor VAG 1315A/1 using jumper wires from VW 1594 adaptor kitswitch ON ignition

control current must be displayed as positive polarity (90-110 mA)

If negative polarity is displayedreverse multimeter test leadsstart engine and let idle

adjust control current using CO adjusting screw 2setting value: 2.5 2.5 mA (fluctuating)

If control current does NOT fluctuatecheck Oxygen sensor (G 39) and Oxygen sensor control, see section 25-100

During adjustment:do not press down on adjusting wrenchdo not accelerate engine with wrench inserted in adjustment screw

After each adjustment:remove adjusting wrench and briefly operate throttle before reading control currentread and then erase Fault memory see Self-diagnosis, Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Ignition timing, idle speed and CO content, checking/adjusting (-90-4)

The following procedure applies to vehicles built after 10-90 starting with control unit:49 States: 8A0 907 404California: 893 907 404 Q

switch OFF ignitionconnect VAG 1551 Diagnostic Tester, see Repair Group D2 for additional information

connect VAG 1367 engine tester using VAG 1367/8 inductive pickup

connect Sun EPA 75 CO tester (or EPA approved equivalent) using VAG 1363/3 adaptor on CO tap tube

NoteAdaptor must be connected tightly to CO tap tube to prevent measuring errors.

start engine and let idlepress 1 button to select "rapid data transfer" modepress 0 and 1 buttons to select "engine electronics"press Q button to enter inputpress buttonpress 0 and 4 buttons to select "initiate basic adjustment" functionpress Q button to enter input

display will appear as shown

Initiate basic adjustment HELPInput display group number XX

press 0 button twice to display group 00display will appear as shown

Initiate basic adjustment QInput display group number 00

press Q button to enter inputdisplay will appear as shown


Initiate basic adjustment QInput display group number 00

press Q button to enter inputdisplay will appear as shown

System in basic adjustment1 2 3 4 5 6 7 8 9

Notethe display channel values are in decimal form2000 is the maximum number of RPM's that can be displayed at this settingwhen this function is selected, the DLS (digital idle stabilizer) is switched off and the carbon canister solenoid valve I is activated

observe channel 9 of displaydisplay value must be 5

lf value other than 5 is displayedread measurement block, see Repair Group D2check ignition timing

checking value: 4 to 8 BTDCIf NO

adjust ignition timing, see Repair Group 28 for additional informationcheck idle speed RPM's (can NOT be adjusted)

must be 800 to 1000 RPMobserve CO content

must be 0.2 to 1.2 volume %If YES

press buttonpress 0 and 6 buttons to select function "end output"press Q button to enter input

If CO content not within specsadjust CO content as followsswitch off ignition


disconnect hoses 1 and 2 from breather housing 3locate such that only fresh air can be drawn inensure that connector piece 4 (with opening) remains in hose 2

switch Fluke 83 multimeter to mA rangedisconnect differential pressure regulator (N 71) harness connector

connect test adaptor VAG 1315A/1 between regulator and harness connector (arrows)connect multimeter to test adaptor VAG 1315A/1 using jumper leads from VW 1594 adaptor kitswitch ignition on

control current polarity (90-110 mA) must be positive (+); if not, swap test connections

start engine and let idlereturn system to "basic setting", see Repair Group D2

adjust control current using CO adjusting screw 2adjusting value: 2.5 2.5 mA (must fluctuate)

If NOcheck Oxygen sensor (G 39) and Oxygen sensor control, Section 25-100

CAUTION!During adjustment;

do not push down on wrench while adjustingdo not accelerate engine while wrench is inserted in adjusting screwremove wrench after each adjustment and briefly raise engine speed before reading multimeter

read and then erase Fault memory, see Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Oxygen sensor and Oxygen sensor control, checking (Page 25-100-1)

Requirementsengine coolant temperature 80 C (176 F) minimumidle adjustment OKno leaks in exhaust system between catalyst and cylinder headvoltage supply for Oxygen sensor heater OK

switch ignition OFFFor vehicles built up to 9-90:

switch Fluke 83 multimeter to mA range disconnect differential pressure regulator (N 71) harness connector

connect test adaptor VAG 1315A/1 between regulator and harness connector (arrows)

connect multimeter to test adaptor VAG 1315A/1 using jumper leads from VW 1594 adaptor kit

switch ignition ON control current polarity (90-110 mA) must be positive (+); if not, swap test connections

start engine and let idle for 2 minutes minimum record control current

clamp crankcase housing breather hose 1 control current must decrease


if NOFor vehicles built up to 7-90:

disconnect OXS harness connector 1 touch wire to control unit (arrow) for approx. 20 seconds

touch ground (-) if necessary, using jumper leads from VW 1594 adaptor kit

For vehicles built after 8-90: disconnect OXS (4 pin) harness connector and OXS heater 1, mounted on right engine mount

touch violet wire from control unit (arrow) to ground for approx. 20 seconds using jumper leads from VW 1594 adaptor kit

If control current changes replace OXS sensor (G 39), see section 25-30 read and then erase Fault memory, see Repair Group D2 for additional information

If control current does not change perform Electrical Test Step 13 in Repair Group D2 and/or replace control unit (J 204)

read and then erase Fault memory, see Repair Group D2 for additional information

For vehicles built after 10-90 starting with control unit:49 States - 8A0 907 404California - 893 907 404Q

connect VAG 1551. Diagnostic Tester using VAG 1551/1 adaptor cable as follows connect VAG 1551/1 black connector to black diagnostic connector 1 in vehicle

display must appear on tester

NoteIf a display does not appear; do not connect white connector. There is a problem with the vehicle power supply to the VAG 1551. Check using wiring diagram, repair or replace as necessary.


After display "V.A.G SELF-DIAGNOSIS" appears connect white VAG 1551 connector to brown and/or white diagnostic connector 2 in vehicle

start engine and let idle press 1 to enter "rapid data transfer" press 0 and 1 to select "engine electronics" press Q button to enter press key press 0 and 8 buttons to select function "read measurement block" press Q button to enter input


Read measurement block HELPInput display group number XX

press 0 button twice to select "Display group 00" 0 display will appear as shown

Read measurement block QInput display group number 00

press Q button to enter input display will appear as shown

Read measurement block1 2 3 4 5 6 7 8 9 10

Continue with testing if the value displayed in channel 1 is less than 63 which corresponds to a coolant temperature of at least 80 C (176 F)

read OXS signal value in channel 6 display must fluctuate

If YES press button press 0 and 6 button to select function "end output" press Q button to enter input


If display does NOT fluctuate disconnect OXS sensor (4-pin) and OXS heater harness connectors

mounted on right engine mount (arrow)

touch violet wire from control unit (arrow) to ground for approx. 20 seconds using jumper wires from VW 1594 adaptor kit

value displayed in channel 6 must increase

If YES replace OXS sensor (G 39), see section 25-30 read and then erase Fault memory, see Repair Group D2

If display value does not increase perform Electrical Test Step 13 in Repair Group D2 and/or replace CIS-E Motronic control unit (J 204)


Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. After start, warm-up and acceleration enrichment, checking (Page 25-110-1)

NoteAcceleration enrichment can also be checked using the VAG 1551 for vehicles built after 10-90 starting with control units:49 states: 8A0 907 404California: 893 907 404QRequirements

engine coolant temperature 60 C (140 F) minimumno faults stored in Fault memory (all faults "repaired" and memory erased)

switch OFF ignition switch Fluke 83 multimeter to mA range disconnect differential pressure regulator (N 71) harness connector

connect test adaptor VAG 1315A/1 between differential pressure regulator and harness connector (arrows)


switch ON ignition control current polarity (90-110 mA) must be positive (+); if not, swap test connections

For vehicles built up to 7-90: disconnect OXS sensor single pin harness connector (arrow)

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. After start, warm-up and acceleration enrichment, checking (Page 25-110-2)

For vehicles built after 8-90: disconnect 4-pin harness connector for Oxygen sensor probe and probe heater, mounted on right engine mount (arrow)

disconnect coolant temperature sensor (G 62) connector

set digital potentiometer VAG 1630 to 2500 Ohms and connect to disconnected harness connector using jumper leads from VW 1594 adaptor kit

start engine and let idle control current must be 10 to 25 mA for approx. 6 to 9 seconds, then control current must again slowly drop back to 5 to 15 mA.

fully (and quickly) open throttle and then close to provide a burst of fuel control current must rise briefly

read and then erase Fault memory, see Repair Group D2.If specified values are not obtained:

perform Electrical Test A in Repair Group D2 and/or replace CIS-E Motronic control unit (J 204)

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Deceleration fuel shut-off, checking (Page 25-120-1)

NoteDeceleration fuel shut-off can also be checked using the VAG 1551 for vehicles built after 10-90 starting with control unit:49 states: 8A0 907 404California: 893 907 404QRequirements

engine coolant temperature 60 C (140 F) minimumno faults stored in Fault memory (all faults "repaired" and memory erased)

switch OFF ignition switch Fluke 83 multimeter to mA range disconnect differential pressure regulator (N 71) harness connector

connect test adaptor VAG 1315A/1 between differential pressure regulator and harness connector (arrows)


switch ON ignition control current polarity (90-110 mA) must be positive (+), if not; swap test connections

start engine and increase engine speed in excess of 3000 RPM close throttle suddenly

control current polarity must briefly become negative

read and then erase Fault memory, see Repair Group D2If control current does NOT become negative

perform Electrical Test A in Repair Group D2 and/or replace CIS-E Motronic control unit (J 204)

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Acceleration enrichment and deceleration fuel shut-off, checking (Page 25-130-1)

For vehicles built after 10-90 starting with control unit:49 states - 8A0 907 404California - 893 907 404QRequirements

engine coldA/C switched OFF

Vehicles with automatic transmission: selector lever in "P or N setting"

connect VAG 1551 Diagnostic Tester using VAG 1551/1 adaptor cable as follows connect VAG 1551/1 black connector to black diagnostic connector 1 in vehicle

display must appear on tester

NoteIf no display appears; do not connect white connector. There is a problem with the vehicle power supply to the VAG 1551. Check using wiring diagram, repair or replace as necessary.After display "VAG SELF-DIAGNOSIS" appears

connect white VAG 1551 connector-to brown and/or white diagnostic connector 2 in vehicle

start engine and let idle operate VAG 1551 depending on display: press 1 button to enter "rapid data transfer"

press 0 and 1 buttons to enter "engine electronics" press Q button to enter input press button press 0 and 8 buttons to enter "read measurement block" function press Q button to enter input



press 0 button twice to select display group 00 display will appear as shown



press Q button to enter input display will show fields 1 through 10


Acceleration enrichment, checkingPerform this check only if channel 9 display value is greater than 96 which corresponds to a coolant temperature below 60 C (140 F).

observe display value in channel 9 quickly open throttle to wide open position and then close again

display value of 70 must appear briefly

The value displayed in channel 9 is the sum of the operating conditions present. This sum is a result of adding together the various conditions present using the following assigned values:Full throttle switch closed = 2+ vehicles with manual or automatic

transmission = 4+ acceleration enrichment activated = 64

= displayed value in channel 9 70

If value of 70 is not obtained perform idle and full throttle switch functional test, see section 25-210

Deceleration fuel shut-off, checkingNotePerform this check only if channel display value in channel 1 is less than 95 which corresponds to a coolant temperature of at least 60 C (140 F).

observe display in channel 9 raise engine speed in excess of 3000 RPM close throttle suddenly

displayed value of 133 must appear briefly


The value displayed in channel 9 is the sum of the operating conditions present. This sum is a result of adding together the various conditions present using the following assigned values:

Idle switch closed = 1+ vehicles with manual or automatic

transmission = 4+ deceleration fuel shut-off activated = 128


read additional values in channel 9 in Function "Measurement block, reading", see Repair Group D2 for additional information

If displayed value of 133 is obtained press button press 0 and 6 buttons to enter function: "end output" press Q button to enter input.

If displayed value of 133 is not obtained perform idle and full throttle switch functional test, see section 25-210 perform electrical testing, Repair Group D2 and if necessary replace CIS-E Motronic control unit (J 204)


Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Speedometer speed signal, checking (Page 25-140-1)

For vehicles built after 10-90 starting with control unit:49 states: 8A0 907 404California: 893 907 404QNoteFor vehicles built before 9-90, check the speedometer speed signal using Electrical Test step 22 in Repair Group D2.For vehicles with manual transmission:

place shift lever in neutral positionFor vehicles with automatic transmission:

place selector lever in "N" position raise left front wheel

connect VAG 1551 Diagnostic Tester using VAG 1551/1 adaptor wire as follows: first connect black connector from VAG 1551/1 to black diagnostic connector 1 after display "VAG SELF-DIAGNOSIS" appears, connect white connector from VAG 1551/1 to brown and/or white diagnostic connector 2

If display does not appear; do not connect white connector check voltage supply to VAG 1551 using wiring diagram

switch ignition ON

press 1 button to enter "rapid data transfer" press 0 and 1 for address word "engine electronics" press Q button to enter input press button press 0 and 8 buttons to obtain "Read measurement block" function press Q button to enter input



press 0 button twice to select display group 00 display will appear as shown

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Speedometer speed signal, checking (Page 25-140-2)


press Q to enter input display shows channels 1 through 10


observe speed signal value in channel 8 manually rotate left front wheel

value must fluctuate between 0 and 1 minimum

If specified value is obtained: press button press 0 and 6 buttons to enter "end output" function press Q button to enter input

If specified values are not obtained: perform multifunction indicator troubleshooting, see Repair Group 91 read and then erase Fault memory, see Repair Group D2

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Coolant temperature sensor, checking (Page 25-150-1)

The following procedure applies to vehicles built after 10-90 starting with control units:49 states: 8A0 907 404California: 893 907 404For vehicles built before 9-90 check the speedometer signal by performing electrical test steps 8 and 23 in Repair Group D2Requirements

engine cold

connect VAG 1551 Diagnostic Tester using VAG 1551/1 adaptor wire as follows: first connect black connector from VAG 1551/1 to black diagnostic connector 1 after "VAG SELF-DIAGNOSIS" display appears, connect white connector from VAG 1551/1 to brown and/or white diagnostic connector 2

If display does not appear; do not connect white connector check voltage supply to VAG 1551 using wiring diagram start engine and let idle press 1 button to enter "rapid data transfer" press 0 and 1 for address word "engine electronics" press Q button to enter input press button press 0 and 8 buttons to obtain "Read measurement block" function press Q button to enter input



press 0 button twice to select display group 00



press Q to enter input display shows channels 1 through 10

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Coolant temperature sensor, checking (Page 25-150-2)


observe value in channel 1 value must drop uniformly and without interruption

If YES press button press 0 and 6 buttons to enter 06 function "end output" press Q button to enter input

If channel 1 display does not drop uniformly (without interruption) replace coolant temperature sensor (G 62) and/or CIS-E Motronic control unit (J 204)

read and then erase Fault memory, see Repair Group D2.

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Cold start valve, checking (Page 25-160-1)

Function, checking perform output checks, see Repair group D2 for additional information

Spray pattern, injection time, and leakage, testing disconnect harness connector from ignition coil power output stage disconnect intake air boot from throttle body

CAUTION!The sensor plate must not be raised during starting because catalytic converter damage could result.

disconnect coolant temperature sensor (G 62) harness connector

preset VAG 1630 digital potentiometer to 15000 Ohms and connect to disconnected harness connector using jumper leads from VW 1594 adaptor kit

remove cold start valve (N 17) and place in a measuring glassWARNING!Fire Hazard! Do not smoke or have anything in area that can ignite fuel.

operate starter cold start valve must spray (pulse) for approx. 8 seconds in a uniform pattern

dry off tip of cold start valve at nozzle within one minute; no drops may fall from the valve tip nor may any fuel dampness be present on tip surface

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Air flow sensor, checking and adjusting (Page 25-170-1)

WARNING!Fire Hazard! Do not smoke or have anything in area that can ignite fuel.Sensor plate lever and control plunger, checking

pull injectors out of inserts and place in openings of VAG 1348/2B fuel analyzer operate either starter or remote control VAG 1348/3A for approx. 10 seconds

to connect remote control, see section 25-190

check quality of sensor plate lever movement by lifting sensor plate bolt using magnet sensor plate lever must exhibit same resistance over entire travel

pull sensor plate upward with a quick movement using a magnet on the sensor plate bolt

no change in lever resistance should be felt

If YES replace air flow sensor assembly

If sensor plate lever is difficult to move upward but moves downward easily replace fuel distributor

control plunger is hanging up

Sensor plate rest position, checking

upper edge of sensor plate must be dimension "a" below cone edge of venturi a= 1.9 + 1.1 mm

Sensor plate rest position, adjusting remove upper section of air filter housing and remove air filter element.


adjust rest position clearance (dimension "a") using adjustment nut (arrow) a=1.9 + 1.1 mm

CAUTION!Do not bend leaf spring while performing adjustment.Sensor plate free play, checkingRequirements

sensor plate rest position OKCO adjustment OK, for checking see idle adjustment, section 25-210

NoteFree play is the clearance between the control plunger and sensor plate lever (right arrow), measured on the side of the sensor plate closest to the fuel distributor (left arrow).

operate starter or remote control VAG 1348/3A for approx. 10 seconds to connect remote control, see section 25-190

lift sensor plate slightly until resistance is felt free play: 0.5 mm minimum

3.0 mm maximum (up to edge of venturi)If free play NOT OK

adjust free play on fuel distributor via control plungerSensor plate free play, adjusting at fuel distributorRequirement

CO adjustment OK, for checking see idle adjustment, section 25-190


adjust sensor plate free play using wrench VW 674/2 on control plunger stop screwdistance "a" = 0.6 mm between stop screw and collar of hex hut1/4 turn = approx. 1.3 mm of play at sensor plateturning in = increases free playturning out = decreases free play

After free play adjustment is completed re-check free play adjustment, if necessary adjust CO content via control current adjustment, see idle adjustment, section 25-190

Sensor plate lever, basic adjustmentNoteThe basic adjustment should only be performed if the fuel distributor or air flow sensor have been replaced.

measure distance between the air flow sensor housing opening (for the fuel distributor) and the sensor plate lever roller, if necessary adjust using CO adjusting screw

must be 21.3 0.1 mm*

* After adjusting CO content to specifications (via control current), this dimension no longer applies.Control plunger, removing

mark position of stop screw by scribing

measure and record distance "a" between stop screw and hex nut collar remove stop screw using VW 674/2 wrench

Control plunger, installing wash control plunger with clean gasoline before installing inspect stop screw sealing ring for damage, replace if necessary

install with smaller diameter 0 of sealing ring towards control plunger


insert stop screw using VW 674/2 wrench until previously recorded dimension "a" is obtained

check sensor plate rest position and free play, adjust if necessary, see section 25-170

NoteMechanically cleaning the control plunger is not permitted. If the piston shows heavy scoring and/or does not move easily after washing with clean gasoline, the complete fuel distributor must be replaced.

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Air flow sensor potentiometer, checking and adjusting (Page 25-180-1)

NoteThe potentiometer is precisely adjusted at the factory; to prevent tampering and/or adjustments the trim and mounting screws are then covered with sealing compound.Requirements

engine coolant temperature 60 C (140 F) minimumdo not take measurements during periods when radiator cooling fan is running

Potentiometer, checking disconnect harness connector from air flow sensor potentiometer

connect VAG 1501 test adaptor between potentiometer (G 19) and potentiometer harness connector (arrows)

switch Fluke 83 multimeter to 20 Volt range connect multimeter to adaptor wires 1 and 3 of VAG 1501 test adaptor using jumper wires from VW 1594 adaptor kit

switch ON ignition must be 4.35 to 5.35 Volts

switch OFF ignition

connect multimeter to adaptor wires 2 and 3 of VAG 1501 test adaptor start engine and let idle for 2 minutes minimum

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Air flow sensor potentiometer, checking and adjusting (Page 25-180-2)

measure voltage and compare to chart U1=voltage measured between adaptor leads 1 and 3U2=voltage between adaptor leads 2 and 3

If U2 voltage falls below tolerance limit check intake system for air leaks

between air flow sensor and cylinder headbetween possibly damaged connector pipe and intake air boot/throttle bodyat carbon canister solenoid valve

If a leak is detected and U2 voltage exceeds tolerance slightly carefully remove sealing compound covering potentiometer trim screw

adjust U2 voltage using trim screw (arrow) try to obtain a nominal voltage within the shaded area of the chart

If an acceptable adjustment is not possible replace air flow sensor assembly cover trim screw with a dab of silicon adhesive sealing compound

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Fuel pressure, checking (Page 25-190-1)

WARNING!Fire Hazard! Do not smoke or have anything in area that can ignite fuel.Requirements

fuse No. 18 OKfuel pumps OK, checking - Repair Group 20whenever a fuel line is disconnected always replace the sealing rings

VAG 1318 pressure tester, connecting

connect VAG 1318 pressure tester to measuring point 1 of fuel distributor using adaptor VAG 1318/4disconnect fuel line 2 from cold start valve (N 17) and connect to VAG 1318 pressure tester

shut-off valve on pressure tester: Position A - open Position B - closed Remote control VAG 1348/3A, connecting

remove fuel pump relay (J 17) from fuse/relay panel, location 12attach VAG 1348/3-2 adaptor wire connector to terminal 4 of fuel pump relay socket in location 12

connect alligator clip for remote control VAG 1348/3A to battery positive (+)System pressure, checking

open VAG 1318 shut-off valve (position A) and operate remote control VAG 1348/3A

system pressure must be 6.1 to 6.6 barIf system pressure is not obtained or is too low

replace fuel pressure regulatorIf system pressure too high

disconnect fuel return line from fuel pressure regulator and provide container to catch overflowrepeat test


If system pressure OKcheck return line for proper flow, repair or replace as necessary

If system pressure too highreplace fuel pressure regulator

Differential pressure, checkingclose VAG 1318 shut-off valve (position B)disconnect harness connector from differential pressure regulator (N 73)operate remote control VAG 1348/3A

differential pressure must be 0.3 to 0.5 bar below system pressureIf differential pressure NOT OK

disconnect thin line from fuel pressure regulator and hold in measuring containercover or plug open connection on fuel pressure regulatoroperate remote control VAG 1348/3A for 1 minute and measure accumulation

must be 130 to 150 cc'sIf NO

replace pressure regulatorreconnect thin line on fuel pressure regulator

If differential pressure OKswitch Fluke 83 multimeter to 2 Amp rangedisconnect harness connector from differential pressure regulator

connect test adaptor VAG 1315A/1 between harness connector and differential pressure regulatorconnect multimeter to test adaptor VAG 1315A/1 using adaptor leads from VW 1594adaptor kitswitch ON ignition

control current must be 90 to 110 mAoperate remote control VAG 1348/3A

differential pressure must be 1.3 to 1.6 bar below system pressureIf differential pressure NOT OK

replace differential pressure regulator


If differential pressure and control current not OKperform Electrical Test A in Repair Group D2, and/or replace CIS-E Motronic control unit (J 204)

Residual pressure, checkingNoteThis check is required only if there are hot start problems.

operate remote control VAG 1348/3A for approx. 5 secondsobserve pressure drop on VAG 1318 gauge

after 10 minutes, there must be a minimum pressure of 3.3 barafter 20 minutes, there must be a minimum pressure of 3.2 bar

If the pressure drop exceeds these specificationscheck fuel pump check valve, see Repair Group 20check sensor plate free play and adjust if necessary, see section 25-170check fuel distributor sealing rings, replace if necessary

If these checks are OKreplace fuel pressure regulator

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Injection quantity comparative measurement (Page 25-200-1)

WARNING!Fire Hazard! Do not smoke or have anything in area that can ignite fuel.Requirement

fuse 18 OKRemote control VAG 1348/3A, connecting

remove fuel pump relay (J 17) from fuse/relay panel, location 12attach VAG 1348/3-2 adaptor wire connector to terminal 4 of fuel pump relay socket in location 12connect alligator clip for remote control VAG 1348/3A to battery positive (+)carefully pull fuel injectors out of their inserts and place complete set into openings of VAG 1348/2B fuel analyzer

ensure that fuel lines are routed smoothly and without kinks

turn and lift adjusting screw 1, slide 2 and knurled nut 4 of sensor plate positioning tool VAG 1348/1A to upper positionplace tool centrally on edge of air flow sensor with point 3 of tool facing fuel distributorhold air flow sensor plate in rest position by handpush slide 2 in to stopturn adjusting screw 1 in until magnetic tip contacts sensor plate mounting bolt

operate remote control and turn adjusting screw 1 out far enough so that start of spray becomes visible at one of the injectorsswitch off remote control and empty analyzer

fuel injectors remain inserted in analyzer


Idle position, fuel injection quantity measuring

pull slide 2 of VAG 1348/1A to first stop (idle simulation)observe spray pattern of injectors during following step

spray pattern must be the same for all injectorsif spray pattern for one injector is different; lift sensor plate up once briefly and repeat test

operate remote control until 20 ml fuel accumulates in one of the tubescompare fuel quantities of injectors with each other while holding analyzer level

maximum permissible deviation between all injectors: 2.0 ml

If fuel quantity between highest and lowest reading differs more than 2.0 mlinterchange those two injectors and repeat test

If difference in quantity changes between the interchanged injectorsreplace those injectors

If injection quantity remains the same after interchanging injectorscheck if fuel line is pinched or if fuel distributor is defective, repair or replace as necessary

Full throttle position, fuel injection quantity measurementempty VAG 1348/2 fuel analyzer

fuel injectors remain inserted in analyzer

pull slide 2 of VAG 1348/1A to second stop (full throttle simulation)observe spray pattern of injectors during following step

spray pattern must be the same for all injectorsif spray pattern for one injector is different; lift sensor plate up once briefly and repeat test

operate remote control until 8.0 ml fuel is obtained in one of the tubescompare fuel quantities of injectors with each other while holding analyzer level

maximum permissible deviation between all injectors: 8.0 ml


If fuel quantity between highest and lowest reading differs more than 8.0 mlinterchange those two injectors and repeat test

If difference in quantity changes between the interchanged injectorsreplace those injectors

If injection quantity remains the same after interchanging injectorscheck if fuel line is pinched or if fuel distributor is defective, repair or replace as necessary

Leak checkingplace air flow sensor plate at rest positionoperate remote control for approx. 2 minutes

fuel injectors must not drip

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Idle and full throttle switches, checking and adjusting (Page 25-210-1)

For vehicles with separate idle and full throttle switches.For vehicles built after 10-90 starting with control units:49 states: 8A0 907 404California: 893 907 404QThe function of the idle and full throttle switches can also be checked using the VAG 1551 Diagnostic Tester, see functional check later in this section.

disconnect harness connector from idle/full throttle switch connector

connect VAG 1501 test adaptor to idle/full throttle switch connectorwiring harness connector remains open

Idle switch (F 60), checking and adjustingswitch Fluke 83 multimeter to resistance range

connect multimeter to adaptor leads 1 and 2 using jumpers from VW 1594 adaptor kit

must be 0 Ohmsopen throttle slightly

idle switch must switch OFF and resistance must increase to infinite Ohmsclose throttle slowly and while doing so check switching point of idle switch using feeler gauge

throttle body free play: between operating lever and throttle leverthrottle body without free play: between throttle lever and idle stop (limiter screw)switch point "a" must occur between 0.15 mm and 0.5 mm as measured between throttle valve lever and stop screw


adjust switch point "a" if necessary, by loosening and moving idle switch (F 60) until specification is obtainedre-tighten idle switch mounting screws and re-check

NoteTo ensure proper switching of idle switch, check operating levers for freedom of movement.Full throttle switch (F 81), checking and adjusting

connect multimeter between adaptor test leads 2 and 3 using jumpers from VW 1594 adaptor kit

must be infinite Ohmsopen throttle completely

idle switch must switch on and resistance decrease to 0 Ohms

mount 3084 protractor on throttle body shaft (2nd stage) and fasten using magnetic adapter 3084/1

NoteIf throttle shaft (2nd stage) is attached with a mounting nut place the protractor without the 3084/1 magnetic adapter on the throttle shaft and if necessary remove the mounting nut.

open throttle fully by hand

close throttle by approx. 30 then push slowly back in direction of full throttle stop (arrow), while doing so check switching point (0 Ohms) of full throttle switch 2

switch point 10 2 before full throttle stopadjust switch point if necessary by moving full throttle switch 2 as necessary, then re-check


The following procedures are for vehicles with idle switch, full throttle switch and throttle potentiometer contained in one assembly located below the throttle body.Idle and full throttle switches, checking and adjustingFor vehicles built after 10-90 starting with control unit:49 states: 8A0 907 404California: 893 907 404QThe idle and full throttle switches can also be checked using the VAG 1551 Diagnostic Tester, see functional check later in this section.

if the potentiometer is replaced in a vehicle with an automatic transmission, the automatic transmission control unit must "learn" the voltage value of the new potentiometer by returning the system to its basic setting, see Repair Group D2 for additional information.

Idle and full throttle switches, checking

connect VAG 1501 test adaptor to idle/full throttle switch connector (white)harness connector remains disconnected

switch Fluke 83 multimeter to resistance rangeconnect multimeter to adaptor leads 1 and 2 using jumpers from VW 1594 adaptor kit

must be 0 Ohmsopen throttle slightly

idle switch must switch OFF and resistance increase to infinite Ohms

slowly close throttle while checking switch point (0 Ohms) of idle switch with feeler gauge between throttle lever and idle stop (limiter screw)

switch point "a" = 0.15 mm to 0.5 mm before idle stopmeasure resistance between adaptor leads 2 and 3

must be infinite Ohmsopen throttle completely

full throttle switch must switch on and resistance decrease to 0 Ohms


Idle and full throttle switches, adjustingNoteThe switching point of the idle switch is the only adjustment possible. The full throttle switch and potentiometer become adjusted as a result of adjusting the idle switch and are not adjusted separately.

remove throttle bodyremove heat shield

loosen potentiometer 1 (arrows)rotate and hold potentiometer first clockwise and then fully counterclockwise (carefully) up to stop

CAUTION!Turn potentiometer using very light force otherwise the throttle will open.

tighten potentiometer in this position and check switching point as described in section 25-180

Idle and full throttle switches, functional testingFor vehicles built after 10-90 starting with control unit:49 states: 8A0 907 404California: 893 907 404QRequirements

A/C switched OFFselector lever in "P or N setting" (vehicles with automatic transmission)


connect VAG 1551 Diagnostic connector using VAG 1551/1 adaptor cable as followsfirst connect black VAG 1551/1 connector to black diagnostic connector 1after "V.A.G SELF-DIAGNOSIS" display appears; connect white VAG 1551/1 connector to brown and/or white diagnostic connector 2

If display does not appear; do not connect white connectorcheck voltage supply to VAG 1551 using wiring diagramswitch ignition ONpress 1 button to enter "rapid data transfer" modepress 0 and 1 buttons to enter "engine electronics"press Q button to enter inputpress buttonpress 0 and 8 buttons to enter function "read measurement block"press Q button to enter input



press 0 button twice to select "Display group number 00"display will appear as shown


press Q button to enter inputdisplay shows channels 1 through 10


observe display value in channel 9displayed value must be 5

NoteThe value displayed in channel 9 is the sum of the operating conditions present. This-sum is a result of adding together the various conditions present using the following assigned values:Idle switch closed = 1+ vehicles with manual or automatic

transmission = 4



open throttle slightlyidle switch must switch on and display in channel 9 must change to 4

Idle and full throttle switches open = 0+ vehicles with manual or automatic

transmission = 4


open throttle completelyfull throttle switch must switch and display value in channel must change to 6

Full throttle switch closed = 2+ vehicles with manual or automatic

transmission = 4


NoteRead additional values in channel 9 in Function "Measurement block, reading", see Repair Group D2 for additional information.If the required display values are obtained

press buttonpress 0 and 6 buttons to enter "end output" functionpress Q button to enter input

If required display values are not obtainedperform electrical testing, Repair Group D2 and if necessary replace CIS-E Motronic control unit (J 204)read and then erase Fault memory, see Repair Group D2 for additional information

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Intake air preheating, checking (Page 25-220-1)

Control flap, checkingRequirement

no leaks in control flap vacuum unitloosen air filter housing upper section and remove air filter element

position air filter housing upper section such that the control flap in the lower section housing can be seendisconnect vacuum unit hose from temperature controller on intake air bootconnect vacuum unit hose to US 8026 hand vacuum pump

operate vacuum pump to check control flap freedom of movement and vacuum unit function

control flap must close OFF cold air pipe 1Temperature regulator, checking

connect vacuum unit hose to temperature controller connector nipple on intake air boot

start engine and let idleposition of control flap after 20 seconds (maximum), depending on temperature controller temperature:below approx. 20 C (68 F) = cold air pipe 1 closedabove 30 C (86 F) = warm air pipe 2 closedbetween 20 C and 30 C (68 to 86 F) = control flap between cold and warm air pipes (both pipes open)

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Vacuum connections (Page 25-230-1)

1 - from carbon canister carbon canister system repairing see Repair Group 20

2 - Carbon canister solenoid valve I (N 80) gray

3 - Carbon canister solenoid valve II (N 115) black

4 - Intake air boot5 - Temperature controller

note installed position6 - Throttle body7 - Intake manifold8 - Check valve

for vehicles without ABS only note installed position: arrow on valve points toward intake manifold

9 - from brake booster for vehicles without ABS only

10 - from multifunction indicator - A/C for vehicles without ABS only vehicles without multifunction indicator - AC: plug off connection on check valve (item

8)11 - from multifunction indicator

for vehicles with ABS for vehicles without multifunction indicator: plug off connection on tee

Volkswagen B3 Passat Fuel Supply-Fuel Injection-Exhaust-Ignition 4 CYL. Vacuum connections (Page 25-230-2)

12 - from A/C for vehicles with ABS for vehicles without A/C, plug off connection on tee

13 - from temperature regulator Item 5 for vehicles with ABS

14 - from idle stabilizer valve (N 71) see section 25-50. Item 19

15 - Vacuum unit for intake air preheating control flap

16 - Air filter housing

Volkswagen Passat B3

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