Engine Controls - Accessing DTC's Using Jumper Wire
90vw01
Subject: Accessing OBD Fault Codes Using Jumper Cable
Model(s): California, Fox/Golf/Jetta/Corrado 1991 m.y.
Group: 24
Number: 91-02
Date: Jan 31, 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
Jumper Cable Assembly:
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.
CAUTION Part numbers are for reference only. Always check with your Parts Department for latest information.
^ 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).
^ 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).
^ 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.
BLINK CODES DIGIFANT I (California)
Component Code
Knock sensor (except Fox) 2142
Throttle valve potentiometer 2212
Intake manifold pressure 2222
sensor (Corrado only)
CO adjustment potentiometer 2242
(Corrado only)
Coolant temperature 2312
Intake air temperature sensor 2322
Air flov sensor 2323
Oxygen sensor 2341
(beyond normal range)
Oxygen sensor 2342
Fuel injectors 4411
ECU (control unit defective) 1111
No faults recorded 4444
End diagnosis 0000