ACCESSNG OBD Fault Codes Using Jumper Cable (GROUP 24, NO. 91-02)

ACCESSNG OBD FAULT CODES USING JUMPER CABLE

TECHNICAL SERVICE BULLETIN

ACCESSING OBD FAULT CODES USING JUMPER CABLE

Model(s): 1991 Volkswagen Fox, Golf, Jetta, Corrado

California Models only

Group: 24 - Multiport Fuel Injection

Bulletin No.: 91-02

Date: January 1, 1991

WARNING LIGHT FUNCTION

Volkswagen Models Equipped with OBD System 

Beginning with 1991 model year, vehicles sold in California are equipped with an On Board Diagnosis (OBD) system. 49 state vehicles are not equipped with this system. Therefore two different engine management systems are required.

For vehicles equipped with the Digifant Engine Management system there are two systems;

• Digifant I for California vehicles
• Digifant II for the 49 state vehicles

FUNCTIONING OF THE OBD SYSTEM

The two systems are similar except the California vehicles (Digifant I) are equipped with the OBD system. The OBD system is incorporated into the Digifant I ECU.

The OBD system detects malfunctions in the engine management system that could cause the vehicle to fail an exhaust emissions test.

Bulb Check Function: 

The warning light will illuminate each time the vehicle is started, to inform the driver that the bulb for the warning light is functional. The light will remain on until the engine is started.

Fault Detection: 

If the OBD system detects a fault, the information will be stored in a permanent fault memory in the ECU. A warning light with the word "CHECK" in the instrument panel, will illuminate to warn the driver that a malfunction has developed.

If a malfunction is detected, the warning light will stay illuminated until the malfunction is repaired and the memory erased.

If the malfunction is temporary, or goes away after a short time, the warning light will go out. However, the fault will remain in memory.

Blink Code: 

The warning light has another function, to display fault codes via a blink code, in the event a V.A.G. 1551 is not available. See chart for blink code explanation.

ACCESSING BLINK CODE

If a V.A.G. 1551 tester is not available, access blink codes using a jumper cable, Part No. 357 971 514E, located in the trunk or glove compartment. See Fig 1 .

- Ignition on or engine idling (1300 RPM Maximum).

- Connect Jumper Cable Part No 357 971 514E, to diagnostic connectors located in center console. Black connector to black diagnostic connector (1), and white connector to white diagnostic connector (2). See Fig 2 .

- Maintain connection for at least 2.5 seconds and remove.

- OBD light on dash will flash first blink code.

- To read additional blink codes, repeat procedure until 0000 is flashed.

- To end blink code read out, connect jumper cable one additional time or turn ignition off.

CLEARING BLINK CODE MEMORY

- Ignition off.

- Connect jumper cable, Part No. 357 971 514E, black connector to black diagnostic connector (1), and white connector to white diagnostic connector (2). See Fig 1 and Fig 2 .

- Turn on ignition.

- Remove jumper cable after 2.5 seconds.

- Blink code will flash 4444. (no faults recorded)

TO END SEQUENCE;

Turn off ignition.

-or-

Connect jumper cable, Part No. 357 971 514E, as described above for 2.5 seconds and disconnect, two times.

Component	Code
Knock sensor (except Fox)	2142
Throttle valve potentiometer	2212
Intake manifold pressure sensor (Corrado only)	2222
CO adjustment potentiometer (Corrado only)	2242
Coolant temperature	2312
Intake air temperature sensor	2322
Air flow sensor	2323
Oxygen sensor (beyond normal range)	2341
Oxygen sensor	2342
Fuel injectors	4411
ECU (control unit defective)	1111
No faults recorded	4444
End diagnosis	0000