Volkswagen B3 Passat Diagnosis, Fault Memory - Passat D2...

Volkswagen B3 Passat Diagnosis, Fault Memory - Passat D2 Diagnosis, Fault Memory (Page GR-D2)

Engine code 9A

Control units WITHOUT functions 04 and 08

CIS-E Motronic systemelectrical testingself diagnosistroubleshootingunderhood component layout

Fault codetable

Fault memoryerasingreading

Output checksdiagnosis

VAG 1551 Diagnostic Testerconnecting

VAG 1598 test boxconnectingdescription

Engine code 9A

Control units WITH functions 04 and 08

Automatic transmission 096returning to basic setting

CIS-E Motronic systemelectrical testingtroubleshootingunderhood component layout

Fault codetable

Fault memoryerasing

readingFunction 08 (VAG 1551, measuring value block)

activatingchannel 1, interpretingchannel 2, interpretingchannel 3, interpretingchannel 4, interpretingchannel 5, interpretingchannel 6, interpretingchannel 7, interpretingchannel 8, interpretingchannel 9, interpretingchannel 10, interpretinggeneral information

Output checksdiagnosis

Self-diagnosisgeneral informationtechnical data

VAG 1551 Diagnostic Testerconnecting selectable functions

VAG 1598 test boxconnectingdescription

Volkswagen B3 Passat Diagnosis, Fault Memory - Passat CIS-E Motronic, self-diagnosis (Page D2-05-1)

NoteLook under General for information about the test equipment, how to hook it up and how to use it.To use the information in this manual you need the right wiring diagram. See wiring diagrams.CIS-E Motronic, self-diagnosisThe procedures in this section apply to the following control units ONLY:893 907 E, F, L, AND MThese procedures are identified at the bottom of each page by the boxed footer:

ECU without 04 and 08 functionsFor other (later) ECU's see next index.The CIS-E Motronic control unit (J 204) features Self-Diagnosis (SD) capability. If problems occur at monitored sensors or components, they are stored in Fault memory.The self diagnosis must be initiated and the stored fault(s) recalled with the tester VAG 1551. The VAG 1551 tester can tap into the Motronic ECU memory via remote diagnostic terminals beneath the center console in front of the shift lever.Faults that occur only occasionally are stored as sporadic faults.CAUTION!Faults related to emissions and safety are stored in a permanent memory which must be intentionally erased after faults have been eliminated or repaired.The CIS-E Motronic control unit is also equipped with an output check diagnosis function.

ECU without 04 and 08 functions

Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Fuel injection system, underhood component layout (Page D2-10-1)

NoteThe CIS-E Motronic control unit contains a fault memory. Display the contents of the fault memory before beginning any repairs. See Repair Group D2 for additional information.WARNING!Fire hazard. Do NOT smoke or have anything in area that can ignite fuel.CAUTION!During checking and adjusting, system limits are sometimes exceeded. These values will be recognized and stored as faults by the control unit.

After all checks and adjustments have been performed, the fault memory should be cancelled. See Repair Group D2 for additional information.This Repair Group only covers the fuel related components of the CIS-E Motronic system. See Repair Group 28 for ignition components.



1 - Harness connector for Oxygen sensor on right engine mount

2 - Throttle body throttle screw must be turned in completely

3 - CIS-E Motronic control unit (J 204)4 - Intake air temperature sensor (G 72)

California only for monitoring function of EGR system

5 - EGR valve (Exhaust Gas Recirculation) California only

6 - CO tap tube7 - Idle stabilizer valve (N 71)8 - Power output stage (N 70) (of Ignition coil)9 - Ignition coil

10 - 6 pin harness connector11 - Ignition distributor with Hall sender12 - Vacuum amplifier (EGR system)

California only13 - Ignition timing sensor (G 4)

on cylinder number 4 ignition wire14 - Thermopneumatic valve (EGR system)

California only15 - Coolant temperature sensor (G 62)16 - Cold start valve (N 17)17 - Knock sensor I (G 61)18 - Fuel Injector19 - Knock sensor 11 (G 66)20 - Control flap for intake air pre-heating21 - Differential pressure regulator (N 73)22 - Fuel distributor23 - Charcoal canister

below air filter24 - Air filter25 - Potentometer26 - Fuel pressure regulator27 - Air flow sensor28 - Solenoid valves 1 and 11 (N 80, N 115) for carbon canister29 - Spark plug

30 - Harness connector for throttle switches (F 60, F 81)


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat CIS-E Motronic system, troubleshooting (Page D2-20-1)

verify complaintsatisfy tuning requirements and adjustments

If the problem still exists:find "symptom" in numbered top sectionscan the vertical column for ALL X'sread across from the X to determine possible causelook up section for appropriate repair information or refer to index of Repair Group indicated

* Also see section D2-90



Troubleshootingverify complaintsatisfy tuning requirements and adjustments

If the problem still exists:find "symptom" in numbered top sectionscan the vertical column for ALL X sread across from the X to determine possible causelook up section for appropriate repair information or refer to index of indicated Repair Group

Also see section D2-90




If the problem still exists:find "symptom" in numbered top sectionscan the vertical column for ALL X'sread across from the X to determine possible causelook up section for appropriate repair information or refer to index of indicated Repair Group

* Also see section D2-90** Also see section D2-50 to perform output check diagnosis


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG Tester 1551, connecting (Page D2-30-1)

Requirements

fuses 15, 18, and 21 OKA/C switched OFFengine ground connections OK, near ignition distributor, at engine block and the ground strap between the cylinder head and the ignition coil power output stage

switch OFF ignitionremove shift lever knobremove console cover

connect VAG 1551 with adaptor cable VAG 1551/1 as followsconnect black wire to black diagnostic connector 1connect white wire to white diagnostic connector 2blue wire not used

VAG - Self Diagnosis HELP1 - Rapid data transfer*

Display alternately appears as shown:

VAG - Self Diagnosis HELP2 - Blink code output*

Notes:For additional operating instructions push the HELP key.

If no display appears, check the voltage supply to the tester.


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Fault memory, reading (Page D2-40-1)

Check Fault memoryAfter connecting the VAG 1551 tester, the display alternates between the following operating modes:

1 - Rapid Data Transfer2 - Blink Code Outputturn on VAG 1551 printer with "print" button

indicator lamp in button lights upswitch ON ignition

Rapid data transfer HELPInsert address word XX

press button 1 to select operating mode "Rapid data transfer"display will appear as shown

Rapid data transfer Q01 - Engine electronics

press buttons 0 and 1 to select "ENGINE ELECTRONICS"display will appear as shown

press Q button to enter input

Rapid data transfer Tester sends address word 01

display will come on briefly to indicate it has sent the address word 01 (check control unit versions)

8AO907404 MOTORCoding 00

then the engine control unit will respond with an identification display which shows the part number, what system it controls, and when it was coded.

If display appears as shown instead:

Rapid data transfer HELPControl unit does not answer!

press HELP key to print out a list of possible failures - after eliminating causes of failure

repeat all inputs from the beginning to obtain the engine control unit identification screen...then proceed

Rapid data transfer HELP

Select Function XX

press buttondisplay will appear as shown



Rapid data transfer Q02 - Check fault memory

press "0" and "2" buttons to select Function 02 "Check Fault memory"display will appear as shown

2 faults recognized!

or

No faults recognized

press Q button to enter inputdisplay will appear as shown

press buttonstored faults are displayed and printed consecutively

After display and print out of the last faultpress buttonselect Function 06 to End Output, and press the Q key to enter that selectioncorrect faults using the fault code table, electrical testing table, wiring diagrams, and output check diagnosis function

Multiple faults may be related, e.g.: low idle speed due to an inoperative idle stabilizer may also result in a Hall sender fault being generated.

For vehicles with an automatic transmission, you MUST return the Digimat system to the basic setting after the following repairs:

engine removal or replacementremoval/replacement/adjustment of the throttle body, throttle cable, or throttle valve potentiometerremoval or replacement of the transmission ECU

see Section D2-110 for additional information

If there is a complaint that has not registered a fault in the self diagnosis memory, perform further testing as per the troubleshooting guide.


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Fault memory, erasing (Page D2-50-1)

after repairing any faults, follow the previous procedure to check Fault memoryAfter display and print out of the last fault:

Rapid data transfer HELPSelect function XX


Rapid data transfer Q05 - Erase Fault memory

press "0" and "5" buttons to select Function 05 "Erase Fault memory"display will appear as shown

Rapid data transferFault memory is erased

press Q button to enter inputdisplay will appear as shownthe Fault memory is now erased

It display appears as shown instead

ATTENTION:Fault memory is not interrogated

follow work procedure sequentially, i.e., first recall faults from memorypress the key to continueselect Function 06 to End Output, and press the Q key to enter that selectiontest drive vehicle for at least 5 minutes

During test drivecoolant temperature must reach 80°C (176°F) minimumengine speed must exceed 3000 RPM at least onceaccelerator pedal must be fully depressed at least once

CAUTION!After test drive, allow engine to idle for at least 2 minutes before checking Fault memory

recall Fault memory, verify that all faults have been corrected


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Output check diagnosis (Page D2-60-1)

NoteThe following components (in the sequence given) can be checked using this procedure.

1 - Differential pressure regulator (N 73)2 - Carbon canister frequency valve (N 80)3 - Idle stabilizer valve (N 71)4 - Cold-start valve (N 17)

After connecting the VAG 1551 tester, the display alternates between the following operating modes:

1 - Rapid Data Transfer2 - Blink Code Outputswitch multimeter US 1119 (or equivalent) to Amps rangeconnect multimeter to differential pressure regulator using VAG 1315A/1 test adaptorswitch ON ignition




press buttons 0 and 1 to select "ENGINE ELECTRONICS"display will appear as shown


Rapid data transfer QTester sends address word 01


8AO907404 MOTORCoding 00

then the engine control unit will respond with an identification display which shows the part number, what system it controls, and where it was coded (as shown in example)




If display appears as shown instead:press HELP key to print out a list of possible failures - after eliminating causes of failure

repeat all inputs from the beginning to achieve the engine control unit identification screen . . . then proceed



Rapid data transfer Q03 - output check diagnosis

press "0" and "3" buttons to select Function 03: "output check diagnosis"display will appear as shown

Output check diagnosisDifferential pressure regulator (N 73)


observe control current on multimetercontrol current must fluctuate from 0 to 100 mA

If NOcheck wiring using wiring diagramcheck differential pressure regulator resistance

If wiring and resistance measurement OKreplace CIS-E Motronic control unit (J 204)

Output check diagnosisCarbon canister frequency valve (N 80)

press buttondisplay will appear as shownfrequency valve must click

If valve does not clickcheck control as follows


remove harness connector from frequency valveconnect LED tester US 1115 (VAG 1527B) to harness connector using VW 1594 adaptor kit

LED must flashIf LED flashes

replace frequency valve (N 80)If LED does NOT flash

check wiringIf wiring OK

replace CIS-E Motronic control unit (J 204)

Output check diagnosisIdle stabilizer valve (N 71)

press buttondisplay will appear as shownidle stabilizer valve must click

If NOcheck control as followsswitch OFF ignitiondisconnect idle stabilizer valve harness connector

connect valve to harness connector using adaptor wires VW 1594/1, /2 and /19connect LED tester to adaptor wire VW 1594/19 using adaptor VW 1594/15repeat output check diagnosis from the beginning

When display: "Idle stabilizer valve (N 71)" has been obtainedLED must flash

If LED flashesreplace idle stabilizer valve

If LED does NOT flashswitch multimeter US 1119 (or equivalent) to resistance rangemeasure idle stabilizer valve resistance

must be 4 to 12 Ohmscheck wiring

If wiring OKreplace CIS-E Motronic control unit (J 204)



Output check diagnosisCold-start valve (N 17)


open throttle slightlycold-start valve must click

NoteThe valve only is activated ten times to avoid "flooding" the engine. To repeat this check, the output check diagnosis must be repeated from the beginning.

If the valve does not click, check control as followsdisconnect cold-start valve harness connectorconnect LED tester to harness connector using adaptor kit VW 1594perform output check diagnosis again from the beginning

When display "cold-start valve (N 17)" is obtainedopen throttle valve slightly

LED must flash ten timesIf LED flashes

replace cold-start valveIf LED does NOT flash


replace CIS-E Motronic control unit (J 204)press the key to continueselect Function 06 to End Output, and press the Q key to enter that selection


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Fault code, table (Page D2-70-1)

Notebefore replacing components coded as faulty, first check the wiring and ground connections to these components using the proper wiring diagramto check wiring, see "CIS-E Motronic system, electrical tests", section D2-90blink code (4 digit) does not appear in display when in rapid data mode

Example: Fault indicator Blink code code (if present) 65535 1111

* Note for Fault Code 1231:Some VAG 1551 Diagnostic Testers will display component code (G68) for this fault. FOR THOSE TESTERS: the display is INCORRECT. The CORRECT component code is (G54).


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG 1598 Test box, description (Page D2-80-1)

The VAG 1598 Test box and adaptor set was introduced in July of 1989. It consists of a main harness with test box (that universally connects to all of the adaptor harnesses) and a set of adaptor harnesses. A hardshell storage case is provided to protect the set when not in use.The VAG 1598 is used in conjunction with several other pieces of test equipment consisting of:

US 1119 (or equivalent) multimeterUS 1115 (VAG 1527B) LED testerVW 1594 adaptor kit

NoteNew adaptor harnesses will be made available for the VAG 1598 in the future as new applications require them.VAG 1598 advantages:

the fragile terminals in the control unit connector no longer risk damage from test leads and probe connections. Connections formerly made on the control unit connector are not made on the VAG 1598 Test box which has large conveniently accessible terminalsraised, highly visible numbers on the Test box eliminate any uncertainty as to connector terminal numberingcertain components (e.g. Hall sender) can now be checked dynamically (engine running)electronically checking miniature and unusual size terminals is now made possible regardless of terminal sizestandard sized adaptors are used to make and test all connections resulting in dependable, accurate measurements


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG 1598 Test box, connecting (Page D2-90-1)

Example: CIS-E Motronic control unitselect the appropriate adaptor harness from the list (based on the connector you wish to connect to) for this example use adaptor harness VAG 1598/3connector adaptor harness VAG 1598/3 to main test box harness by joining the two rectangular connectors, then tighten via knobs on main harness connector

NoteThe rectangular connector which is on every adaptor cable can only be installed one way. Examine the connector and you will see where the threaded connectors of the Test box harness attach to the adaptor connector.

disconnect CIS-E Motronic control unit harness connector 1 from control unit 2connect test adaptor VAG 1598/3 male connector to control unit harness connector 1

NoteIn this example the wiring up to the control unit is being checked statically, making it unnecessary to connect the control unit to the adaptor harness; however, for dynamic checks you will have to connect the control unit.


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat CIS-E Motronic system, electrical testing (Page D2-100-1)

Requirements before testingvoltage supply (alternator, battery) OKstarter operates OKwiring and connectors OK (not corroded, terminals properly seated, etc.)fuses 15 and 18 OKCIS-E Motronic control unit ground wires OK (near ignition distributor connection)fuel pumps and fuel pump relay OKcheck control unit for stored faults using VAG 1551, eliminate faults as necessary

NoteBefore replacing a component whose measured value deviates from the specified value; first check all connections and wiring to the component using the wiring diagram then check component resistance (if possible).

use the following test instruments to perform the electrical tests in this section: US 1119 or equivalent multimeter, US 1115 (VAG 1527B) LED tester, VW 1594 adaptor kit, VAG 1598 Test box with the VAG 1598/3 adaptor cableconnect test instruments to Test box terminals using VW 1594 adaptor kitterminal numbers of component connectors and terminal numbers on Test box are the samethe specifications given are valid ONLY when measured within an ambient temperature range of 0° to + 40°C (+32° to + 104°F)

CAUTION!Perform the following electrical tests with great care. The CIS-E Motronic control unit could be destroyed if the following precautions are NOT observed:

ALWAYS switch the multimeter to the desired units and range of measurement (Volt, Ohms, etc.) BEFORE making connections to the Test boxdo NOT connect or disconnect adaptors/test instruments to the Test box while the ignition is switched ON



switch OFF ignitionswitch multimeter US 1119 (or equivalent) to 20 Volts DC rangedisconnect CIS-E Motronic control unitconnect VAG 1598 Test box to control unit harness connector using VAG 1598/3 adaptor cable

CIS-E Motronic control unit 1 is NOT connected during the following tests



Also see airflow sensor potentiometer dynamic test in Repair Group 25, page 25-180-1



CAUTION!Perform the following electrical tests with great care. The CIS-E Motronic control unit could be destroyed if the following precautions are NOT observed.

ALWAYS switch the multimeter to the desired units and range of measurements (Volts, Ohms, etc.) BEFORE making connections to the Test boxDo NOT connect or disconnect adaptors/test instruments to the Test box when the ignition is switched ON

The following tests are performed with the control unit harness connector AND the control unit connected to the VAG 1598/3 adaptor cable).

switch OFF ignitionconnect free end of VAG 1598/3 adaptor cable to control unitswitch multimeter US 1119 (or equivalent) to 20 Volt range


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Automatic transmission 096, returning to basic setting (Page D2-110-1)

NoteYou MUST return the Digimat system to the basic setting after the following repairs:


Perform the basic setting anytime you are not sure if it has been done. It only takes a moment and will ensure that you do not receive a complaint due to someone else's oversight.After connecting the VAG 1551 tester, the display alternates between the following operating modes:

1 - Rapid Data Transfer2 - Blink Code Outputswitch ON ignition



Rapid data transfer Q02 - Transmission electronics

press buttons 0 and 2 to select "Transmission electronics"display will appear as shown




095927731 F Digimat 0569Code 127 WSC131071

then the transmission control unit will respond with an identification display which shows the part number, what system it controls, the EPROM programming level. and where it was coded





repeat all inputs from the beginning to achieve the transmission control unit identification screen . . . then proceed



NoteBefore performing the "return to basic setting" you must first determine that full accelerator pedal travel is present. Perform the following procedure to digitally display the throttle position and travel.

Rapid data transfer Q08 Read measuring value block

press buttons 0 and 8 to select Function 08 "Read measuring value block"display will appear as shown

Read measuring value block Input display group number XX


NoteThe measuring block values can only be read with the tester program card /2 installed.

Read measuring value block QInput display group number 00

press 0 button two timesdisplay will appear as shown

Read measuring value block0 1 0 0 17 0 242 250 19 3


Read measuring value blockP 0.37V 0% 00000111

one of the 2 displays shown will appear, dependent upon the production level of the DIGIMAT transmission control unit

To check accelerator travelobserve displayed values first with pedal in idle position then in full-throttle position


10 channel display, observe value in channel 2 (arrow)must read 0-2 (idle position)must read 253-255 (full throttle)



press button

Read measuring value block 1P 0.37V 0% 00000111

4 channel display, observe value in channel 3 (arrow)must read 0-1% (idle position)must read 99-100% (full throttle)

If readings are not within specificationscheck throttle valve position with pedal at idle and full throttle positions

must be fully closed at idle and wide open when pedal is fully depressed to floorIf NO

check accelerator cable condition and adjustment, adjust or replace if necessaryIf YES

check throttle potentiometer adjustment, adjust or replace if necessary



Rapid data transfer Q04 - Start basic setting

press buttons 0 and 4 to select Function 04 "Basic setting"display will appear as shown

Start basic setting HELPInput display group number XX


Start basic setting QInput display group number 00


System in basic setting


depress accelerator pedal fully to floor for 5 seconds



After 5 seconds, with accelerator pedal fully depressedpress keyrelease accelerator pedal

system has now been returned to the basic settingselect Function 06 to End Output, and press the Q key to enter that selection


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat CIS-E Motronic, self-diagnosis (Page D2-120-1)

The procedures in this section apply to the following control units ONLY:Starting October 1990:49 States & Canada 8A0 907 404California 893 907 404QThese procedures are identified at the bottom of each page by the boxed footer:

ECU with 04 and 08 functionsFor other (later) ECU's see next index.The CIS-E Motronic control unit (J 204) features Self-Diagnosis (SD) capability. If problems occur at monitored sensors or components, they are stored in Fault memory.The self diagnosis must be initiated and the stored fault(s) recalled with the tester VAG 1551. The VAG 1551 tester can tap into the Motronic ECU memory via remote diagnostic terminals beneath the center console in front of the shift lever.Faults that occur only occasionally are stored as sporadic faults and are indicated in the VAG 1551 display by "SP".If a Fault does not occur within 5 engine starts or for exhaust related faults within the next 50 starts, the sporadic fault will automatically be erased.CAUTION!Faults related to emissions and safety are stored in a permanent memory which must be intentionally erased after faults have been eliminated or repaired.The CIS-E Motronic control unit is also equipped with an output check diagnosis function.

ECU with 04 and 08 functions


NoteThe CIS-E Motronic control unit contains a fault memory. Display the contents of the fault memory before beginning any repairs.WARNING!Fire hazard. Do NOT smoke or have anything in area that can ignite fuel.CAUTION!During checking and adjusting system limits are sometimes exceeded. These values will be recognized and stored as faults by the control unit.Alter all checks and adjustments have been performed the fault memory should be erased.



1 - Harness connector for Oxygen sensor on right engine mount

2 - Throttle body throttle screw must be turned in completely

3 - CIS-E Motronic control unit (J 204)4 - Intake air temperature sensor (G 72)

California only for monitoring function of EGR system

5 - EGR valve (Exhaust Gas Recirculation) California only

6 - CO tap tube7 - Idle stabilizer valve (N 71)8 - Power output stage (N 70) (of ignition coil)9 - Ignition coil

10 - 6 pin harness connector11 - Ignition distributor with Hall sender12 - Vacuum amplifier (EGR system)

California only13 - Ignition timing sensor (G 4)

on cylinder number 4 ignition wire14 - Thermopneumatic valve (EGR system)

California only15 - Coolant temperature sensor (G 62)16 - Cold start valve (N 17)17 - Knock sensor I (G 61)18 - Fuel injector19 - Knock sensor II (G 66)20 - Control flap for intake air pre-heating21 - Differential pressure regulator (N 73)22 - Fuel distributor23 - Carbon canister

below air filter24 - Air filter25 - Potentiometer26 - Fuel pressure regulator27 - Air flow sensor28 - Solenoid valves I and II (N 80 N 115) for carbon canister29 - Spark plug

30 - Harness connector for throttle switches (F 60, F 81)


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Self Diagnosis, Technical Data (Page D2-140-1)

1) Erased after 5th engine start, if faults no longer occur.2) For vehicles 10.90 (beginning with Parts No. of CIS-E Motronic control unit US-49 states and

Canada 8A0 907 404, California 893 907 404Q) before idle adjustment or ignition timing point return system to basic setting. See Repair Group 25 or 28.


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG 1551 Diagnostic Tester, selectable functions (Page D2-150-1)

(X) = also possible.1) Starting October 1990 Production with control unit: 49 States and Canada 8A0 907 40

California 893 907 404 Q.



verify complaintsatisfy tuning requirements and adjustments

If the problem still exists:find "symptom" in numbered top sectionscan the vertical column for ALL X'sread across from the X to determine possible causelook up section for appropriate repair information or refer to index of Repair Group indicated

* Also see section D2-200


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG Tester 1551, connecting (Page D2-170-1)

Requirementsfuses 15, 18, and 21 OKA/C switched OFFengine ground connections OK, near ignition distributor, at engine block and the ground strap between the cylinder head and the ignition coil power output stage

switch OFF ignitionremove shift lever knobremove console cover

connect VAG 1551 with adaptor cable VAG 1551/1 as followsconnect black wire to black diagnostic connector 1connect white wire to white diagnostic connector 2blue wire not used


Display must alternately appear as shown:


If no display appears:check the voltage supply to the tester

verify that the wiring polarity is correct, repair or replace as necessaryNote

For additional operating instructions push the HELP key.



Check Fault memoryAfter connecting the VAG 1551 tester, the display alternates between the following operating modes:

1 - Rapid Data Transfer2 - Blink Code Outputturn on VAG 1551 printer with "print" button

indicator lamp in button lights upswitch ON ignition




press buttons 0 and 1 to select "Engine electronics"display will appear as shown


Rapid data transfer HELPTester sends address word 01


8A0907404 MOTORCoding 00

then the engine control unit will respond with an identification display which shows the part number, what system it controls, and where it was coded



press HELP button to print out a list of possible failures - after eliminating causes of failure

repeat all inputs from the beginning to obtain the engine control unit identification screen . . . then proceed

Rapid data transfer HELP

Select function XX




Rapid data transfer Q02 - Check fault memory

press "0" and "2" buttons to select Function 02 "Check Fault memory"display will appear as shown

2 faults recognized!


No fault recognized

or (example only)press button

stored faults are displayed and printed consecutivelyAfter display and print out of the last fault

press buttonselect Function 06 to End output, and press the Q button to enter that selectioncorrect faults using the fault code table, electrical testing table, wiring diagrams, and output check diagnosis function

Multiple faults may be related, e.g.: low idle speed due to an inoperative idle stabilizer may also result in a Hall sender fault being generated.

For vehicles with an automatic transmission, you MUST return the Digimat system to the basic seeing after the following repairs:


see section D2-370 for additional information



CAUTION!If ignition is switched off or engine is left running between reading and erasing Fault memory; Fault memory will not be erased.

after repairing any faults, follow the previous procedure to check Fault memoryAfter display and print out of the last fault:



Rapid data transfer HELP05 - Erase Fault memory

press "0" and "5" buttons to select Function 05 "Erase Fault memory"display will appear as shown

Rapid data transfer Fault memory is erased

press Q button to enter inputdisplay will appear as shownthe Fault memory is now erased


ATTENTION! Fault memory is not interrogated

follow work procedure sequentially, i.e., first recall faults from memorypress the key to continueselect Function 06 to End output, and press the Q button to enter that selectiontest drive vehicle for at least 5 minutes



During test drivecoolant temperature must reach 80.C (176°F) minimumengine speed must exceed 3000 RPM at least onceaccelerator pedal must be fully depressed at least once

CAUTION!After test drive, allow engine to idle for at least 2 minutes before checking Fault memory.

read Fault memory,verify that all faults have been corrected



Requirementsfuses 15 and 21 OKidle switch OK (closed)ground wire connections OK (at intake manifold and battery)ignition switched OFF

NoteThe following components (in the sequence given) can be checked using this procedure.

1 - Differential pressure regulator (N 73)2 - Carbon canister frequency valve (N 80)3 - Idle stabilizer valve (N 71)4 - Cold-start valve (N 17)

After connecting the VAG 1551 tester, the display alternates between the following operating

modes: 1 - Rapid Data Transfer2 - Blink Code Outputswitch multimeter US 1119 (or equivalent) to Amps rangeconnect multimeter to differential pressure regulator using VAG 1315A/1 test adaptorswitch ON ignition

display must appear positive, if not, reverse meter leads




press buttons 0 and 1 to select "Engine electronics"display will appear as shown






8A0907404 MOTORCoding 00

then the engine control unit will respond with an identification display which shows the part number, what system it controls, and where it was coded (as shown in example)


If display appears as shown insteadpress HELP button to print out a list of possible failures-after eliminating causes of failure

repeat all inputs from the beginning to achieve the engine control unit identification screen then proceed



Rapid data transfer Q03 - Output check diagnosis

press "0" and "3" buttons to select Function 03 "Output check diagnosis"display will appear as shown

Output check diagnosisDifferential pressure regulator (N 73)


observe control current on multimetercontrol current must fluctuate from 0 to 100 mA

If NOcheck wiring using wiring diagram

check differential pressure regulator resistanceIf wiring and resistance measurement OK


Output check diagnosis Carbon canister frequency valve (N 80)

press buttondisplay will appear as shownfrequency valve must click

If valve does not clickcheck control as follows



remove harness connector from frequency valveconnect LED tester US 1115 (VAG 1527B) to harness connector using VW 1594 adaptor kit

LED must flashIf LED flashes

replace frequency valve (N 80)If LED does NOT flash



Output check diagnosisIdle stabilizer valve (N 71)

press buttondisplay will appear as shownidle stabilizer valve must click

If NOcheck control as followsswitch OFF ignitiondisconnect idle stabilizer valve harness connector

connect valve to harness connector using adaptor wires VW 1594/1, /2 and /19connect LED tester to adaptor wire VW 1594/19 using adaptor VW 1594/15repeat output check diagnosis from the beginning

When display: "Idle stabilizer valve (N 71)" has been obtainedLED must flash

If LED flashesreplace idle stabilizer valve

If LED does NOT flashswitch multimeter US 1119 (or equivalent) to resistance rangemeasure idle stabilizer valve resistance

must be 4 to 12 Ohmscheck wiring

If wiring OKreplace CIS-E Motronic control unit (J 204)



Output check diagnosisCold-start valve (N 17)


open throttle slightlycold-start valve must click

NoteThe valve is only activated ten times to avoid flooding the engine. To repeat this check, the output check diagnosis must be repeated from the beginning.

If the valve does not click, check control as followsdisconnect cold-start valve harness connectorconnect LED tester to harness connector using adaptor kit VW 1594perform output check diagnosis again from the beginning

When display "Cold-start valve (N 17)" is obtainedopen throttle valve slightly

LED must flash ten timesIf LED flashes

replace cold-start valveIf LED does NOT flash

check wiring, section D2-360 Test Step 11If wiring OK

replace CIS-E Motronic control unit (J 204)press the key to continue


display will appear as shown

press 0 and 6 buttons

Rapid data transfer Q06 - Ending output

display must appear as shownpress Q key to enter input



Notebefore replacing components coded as faulty, first check the wiring and ground connections to these components using the proper wiring diagramto check wiring, see "CIS-E Motronic system, electrical tests", section D2-360blink code (4 digit) does not appear in display when in rapid data mode

Example: Fault indicator Blink code code (if present) 65535 1111

* Note for fault code 1231:Some VAG 1551 Diagnostic Testers will display component code (G 68) for this fault. FOR THOSE TESTERS: the display is INCORRECT. The CORRECT component code is (G 54).


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Test value block (Function 08), activating (Page D2-220-1)

For control units starting October 1990:49 States and Canada: 8A0 908 404California: 893 907 404 QNoteWhen using Function 08 "Reading measuring value block" only one channel can be displayed at a time. The channel is indicated by the 00 portion of the display.Requirements

fuses 15 and 31 OKECU (at intake manifold) and battery ground connections OK

connect VAG 1551 Diagnostic Tester using adaptor cable VAG 1551/1 as followsfirst connect black terminal of tester to black diagnostic connector 1

alternating displays will appear as shown


or


connect white terminal of tester to brown or white diagnostic connectorIf no display (no power to tester)

do not connect white terminal of testercheck diagnostic connector voltage supply using wiring diagram, repair or replace as

necessary.start engine and let idleobserve display on VAG 1551 Diagnostic Testerpress 0 and 1 buttons to obtain "rapid data transfer" mode


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat Test value block (Function 08), activating (Page D2-220-2)

press Q button to enter inputpush buttonpress 0 and 8 buttons to obtain Function 08 "Read measuring value block"press Q button to enter input

display will appear as shown

Read measuring value block HELPInsert display group number XX

press 0 button twice to select "Indicator Group 00"display will appear as shown

Read measuring value block QInput indicator group number 00

press Q button to enter inputdisplay will appear as shown (values 1 through 10 = channels)

Reading measuring value block1 2 3 4 5 6 7 8 9 10

Notesindicator group 00 shows only "Reading measuring value block" values are shown in decimal form.when the 08 Function is selected, DIS (digital idle stabilization) and the carbon canister solenoid valve 1 continue to operate.the channel test values are continuously displayed regardless of RPM range.

NoteFor a detailed description of channels see sections D2-230 to D2-330.

push buttondisplay will appear as shown


push 0 and 6 buttons to select Function 06 "Ending output"display will appear as shown

Rapid data transfer Q06 - Ending output


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG 1551 Function 08, channel identification (Page D2-230-1)


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG 1551 Function 08, channel 1 interpretation (Page D2-240-1)



CAUTION!If adjustments are required, use the Repair Manual procedures not the VAG 1551.



This number is not adjustable. If not within working range you must check all other engine adjustments, vacuum leaks, and the mechanical condition of the engine. Since this is an adaptive value it will take approximately 4 minutes or more to adapt itself after a correction is made.



These values are not adjustable. If not within working range you must check all other engine adjustments, vacuum leaks, and the mechanical condition of the engine.



A Value of 50 Equals + 10 Milliamps of Differential Pressure Regulator CurrentA Value of 0 Equals 0 Milliamps of Differential Pressure Regulator CurrentA Value of 206 Equals -10 Milliamps of Differential Pressure Regulator CurrentIf adjustments are required, follow the Repair Manual procedures. Adjustments cannot be made using the VAG 1551 alone.



A Value of 228 Equals +10 Milliamps of Differential Pressure Regulator CurrentA Value of 128 Equals 0 Milliamps of Differential Pressure Regulator CurrentA Value of 228 Equals -10 Milliamps of Differential Pressure Regulator Current



This is a digital signal and only represents and on/off signal



Channel 9, interpretingChannel 9 provides the technician with essential information that would have to be verified manually before performing the basic engine settings.The ECU scans the system for certain conditions that must be met or for certain components that must be present or operative. It then assigns the numerical values (listed in the table below) to these conditions or components and adds them together to create the display value.A value of zero will be assigned to conditions or components in the following chart that are NOT MET or NOT PRESENT.

NoteBy analyzing the value displayed in channel 9 (using simple addition or subtraction) you can easily determine if a component is present or not.

Display Example

Idle Switch Closed 1

Auto Trans in Neutral 4

A/C Compressor On

8

Total 13

(Displayed in Channel 9)


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG 1598 Test box, description (Page D2-340-1)

The VAG 1598 Test box and adaptor set consists of a main harness with Test box (that universally connects to all of the adaptor harnesses) and a set of adaptor harnesses. A hardshell storage case is provided to protect the set when not in use.The VAG 1598 is used in conjunction with several other pieces of test equipment consisting of:

US 1119 (or equivalent) multimeterUS 1115 (VAG 1527B) LED testerVW 1594 adaptor kit

NoteNew adaptor harnesses will be made available for the VAG 1598 in the future as new applications require them.VAG 1598 advantages:

the fragile terminals in the control unit connector no longer risk damage from test leads and probe connections. Connections formerly made on the control unit connector are now made on the VAG 1598 Test box which has large conveniently accessible terminalsraised, highly visible numbers on the Test box eliminate any uncertainty as to connector terminal numberingcertain components (e.g. Hall sender) can now be checked dynamically (engine running)electronically checking miniature and unusual size terminals is now made possible regardless of terminal sizestandard sized adaptors are used to make and test all connections resulting in dependable, accurate measurements


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat VAG 1598 Test box, connecting (Page D2-350-1)

Example: CIS-E Motronic control unitselect the appropriate adaptor harness from the list (based on the connector you wish to connect to) for this example use adaptor harness VAG 1598/3connector adaptor harness VAG 1598/3 to main test box harness by joining the two rectangular connectors, then tighten via knobs on main harness connector

NoteThe rectangular connector which is on every adaptor cable can only be installed one way. Examine the connector and you will see where the threaded connectors of the Test box harness attach to the adaptor connector.

disconnect CIS E Motronic control unit harness connector 1 from control unit 2connect test adaptor VAG 1598/3 male connector to control unit harness connector 1

NoteIn this example the wiring up to the control unit is being checked statically, making it unnecessary to connect the control unit to the adaptor harness; however, for dynamic checks you will have to connect the control unit.



Requirements before testingvoltage supply (alternator, battery) OKstarter operates OKwiring and connectors OK (not corroded, terminals properly seated, etc.)fuses 15, 18 and 2 OKCIS-E Motronic control unit ground wires OK (intake manifold ground connection)fuel pumps and fuel pump relay OKcheck control unit for stored faults using VAG 1551, eliminate faults as necessary

NoteBefore replacing a component whose measured value deviates from the specified value; first check all connections and wiring to the component using the wiring diagram then check component resistance (if possible).

use the following test instruments to perform the electrical tests in this section: US 1119 or equivalent multimeter, US 1115 (VAG 1527B) LED tester, VW 1594 adaptor kit, VAG 1598 Test box with the VAG 1598/3 adaptor cableconnect test instruments to Test box terminals using VW 1594 adaptor kitterminal numbers of component connectors and terminal numbers on Test box are the samethe specifications given are valid ONLY when measured within an ambient temperature range of 0° to + 40°C (+32° to + 104°F)

CAUTION!Perform the following electrical tests with great care. The CIS-E Motronic control unit could be destroyed if the following precautions are NOT observed:

ALWAYS switch the multimeter to the desired units and range of measurement (Volt, Ohms, etc.) BEFORE making connections to the Test boxdo NOT connect or disconnect adaptors/test instruments to the Test box while the ignition is switched ON



switch OFF ignitionswitch multimeter US 1119 (or equivalent) to 20 Volts DC rangedisconnect CIS-E Motronic control unitconnect VAG 1598 Test box to control unit harness connector using VAG 1598/3 adaptor cableCIS-E Motronic control unit 1 is NOT connected during the following tests

NoteTo test terminals 25 + 31 (for automatic transmission vehicles only); read Fault memory for automatic transmission see Repair Group D3 for additional information.


Also see airflow sensor potentiometer dynamic test in Repair Group 25, page 25-180-1



The following tests are performed with the control unit harness connector AND the control unit connected to the VAG 1598/3 adaptor cable).

switch OFF ignitionconnect free end of VAG 1598/3 adaptor cable to control unitswitch multimeter US 1119 (or equivalent) to 20 Volt range

CAUTION!Perform the following electrical tests with great care. The CIS-E Motronic control unit could be destroyed if the following precautions are NOT observed.

ALWAYS switch the multimeter to the desired units and range of measurements (Volts, Ohms, etc.) BEFORE making connections to the Test boxdo NOT connect or disconnect adaptors/test instruments to the Test box when the ignition is switched ON

* Measure directly between actual ground point on manifold and terminal 35 of VAG 1598 Test box.

** If greater than 60 mV check ground connection at intake manifold and clean or repair as necessary



NoteYou MUST return the Digimat system to the basic setting after the following repairs:


Perform the basic setting anytime you are not sure if it has been done. It only takes a moment and will ensure that you do not receive a complaint due to someone else's oversight.After connecting the VAG 1551 tester, the display alternates between the following operating modes:

1 - Rapid Data Transfer2 - Blink Code Outputswitch ON ignition



Rapid data transfer Q02 - Transmission electronics

press buttons 0 and 2 to select "Transmission electronics"display will appear as shown




095927731 F Digifant 0569Code 127 WSC131071

then the transmission control unit will respond with an identification display which shows the part number, what system it controls, the EPROM programming level, and where it was coded





repeat all inputs from the beginning to achieve the transmission control unit identification screen . . . then proceed



NoteBefore performing the "return to basic setting" you must first determine that full accelerator pedal travel is present. Perform the following procedure to digitally display the throttle position and travel.

Rapid data transfer Q08 - Read measuring value block

press buttons 0 and 8 to select Function 08 "Read measuring value block"display will appear as shown

Read measuring value block Input display group number XX


NoteThe measuring block values can only be read with the tester program card /2 installed.

Read measuring value block QInput display group number 00




Read measuring value block P 0.37V 0% 00000111

one of the 2 displays shown will appear, dependent upon the production level of the DIGIMAT transmission control unit



To check accelerator travel


observe displayed values first with pedal in idle position then in full-throttle position10 channel display, observe value in channel 2 (arrow)must read 0-2 (idle position)must read 253-255 (full throttle)

press button

Read measuring value block P 0.37V 0% 00000111

4 channel display, observe value in channel 3 (arrow)must read 0-1% (idle position)must read 99-100% (full throttle)

If readings are not within specificationscheck throttle valve position with pedal at idle and full throttle positions

must be fully closed at idle and wide open when pedal is fully depressed to floorIf NO

check accelerator cable condition and adjustment adjust or replace if necessaryIf YES

check throttle potentiometer adjustment, adjust or replace if necessary



Rapid data transfer Q04 - Start basic setting

press buttons 0 and 4 to select Function 04 "Basic setting"display will appear as shown

Start basic setting HELPInput display group number XX


Start basic setting HELPInput display group number 00




System in basic setting


depress accelerator pedal fully to floor for 5 secondsAfter 5 seconds, with accelerator pedal fully depressed

press keyrelease accelerator pedal

system has now been returned to the basic settingselect Function 06 to End output, and press the Q key to enter that selection


Volkswagen B3 Passat Diagnosis, Fault Memory - Passat D2...

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