Only California vehicles with the Digifant II and Digifant I systems were equipped with the capability of flashing diagnostic codes.
On the Digifant II system codes were viewed through a combination rocker switch/indicator light. The following California vehicles were equipped with the Digifant II system:
1990 Golf, Jetta and GTI with 2.0L 16 valve engine
1990 Cabriolet with engine code 2H
On the Digifant I system a jumper cable would have to be connected and then the codes would flash from the CHECK engine light on the dash. The following California vehicles were equipped with the Digifant I system:
1990-93 Fox - Digifant I
1991-93 Cabriolet - Digifant I
On all other systems, codes can only be retrieved with the use of a special diagnostic tester, the VAG 1551. This tester is available at car dealerships. The VAG 1551 tester can be used on all vehicles that have code capability.
DIGIFANT II SYSTEM-ROCKER SWITCH METHOD
California models are the only vehicles equipped with the On-Board Diagnostic (OBD) lamp. On these models codes may be accessed by 2 methods. The first is the use of a combination rocker switch/lamp located on the instrument panel. The second is used by the dealers, they use a special tool called the VAG 1551.
An indicator light labeled CHECK is located in a rocker switch on the instrument panel. Each time the engine is started, the indicator light will flash once to inform the operator the bulb is working.
The light will come on and stay on if a fault develops in the engine management system. It will also display diagnostic codes to assist in trouble diagnosis.
A diagnostic code consists of 4 groups of flashes. There is a 2.5 second pause (light OFF), between each group of flashes.
The indicator light will come on for two and half seconds prior to displaying a fault code when the diagnostic procedure has been activated. The fault code will continue repeating while the ignition is ON .
If the fault is not repaired the indicator light will come on and stay on when the ignition is turned ON to signify the fault still exists.
The following California vehicles were equipped with the Digifant II system:
1990 Golf, Jetta and GTI with 2.0L 16 valve engine
1990 Cabriolet with engine code 2H
Prior to checking for codes, drive the vehicle for 10 minutes or more.
- Turn the ignition to the ON position, do not start the engine.
- Press and hold down the rocker switch for 4-6 seconds then release the switch. The CHECK indicator lamp will begin flashing a diagnostic code.
- Press and hold down the rocker switch again for 4-6 seconds then release it. The indicator lamp will flash the next diagnostic code and will continue until all codes have been displayed. When all diagnostic codes have been displayed, the indicator lamp will flash a series of 2.5 second flashes ON and 2.5 seconds OFF. This is an 'End Of Fault Sequence' code. If there are no faults stored in the control unit memory, the indicator lamp will flash Code 4444.
DIGIFANT I SYSTEM-JUMPER CABLE METHOD
California models are the only vehicles equipped with the On-Board Diagnostic (OBD) lamp. On these models codes may be access by 2 methods. The first is the use of a special jumper cable connected to the diagnostic connector. The second is used by the dealers, they use a special tool called the VAG 1551.
The following California vehicles were equipped with the Digifant I system:
- Verify that all the fuses and grounds in the engine compartment are good.
- Turn the ignition key ON .
- Connect jumper cable 357 971 514E or equivalent to the connectors located in the center console. The black end of jumper wire connects to the black diagnostic connector in the console. The white end of the jumper wire connects to white diagnostic connector in the console.
- Connect the jumper wire for about S seconds. When the OBD light begins flashing, remove the jumper wire.
- Count the flashes of the light to get codes, each separate flash, in one code, will be have a short interval in between. Each interval between codes will be about 2.5 seconds. Count flashes until either Code 4444 or 0000 appears. To end this procedure turn the ignition switch OFF .
- Output checks can not be performed without a diagnostic tester.
DIGIFANT I SYSTEM-WITH DIAGNOSTIC TESTER
This method is used by the Dealers and requires the use of the special tester VAG 1551. The following vehicles can only be accessed using this tester:
- Make sure ignition switch is OFF and that all fuses are good. Make sure all grounds in engine compartment are good, especially those for the battery and control module.
- Make sure the air conditioning system is OFF.
- Connect the VAG 1551 diagnostic tester using VAG 1551/1 Adapter cable or equivalent. The diagnostic connectors are located in the center console, under the shifter. The shifter knob and console cover must be removed to access diagnostic connectors. Connect diagnostic connector 1 (black) to the black connector on the scan tool. Connect diagnostic connector 2 (white) to the white connector on the scan tool. The blue connector is not required.
- Turn the ignition switch ON ; now start the vehicle and let it idle. If vehicle will not start, crank engine for 6 seconds and leave ignition ON .
- Turn the tester ON and make sure it is receiving power. The screen will display 2 menu options; Rapid Data Transfer and Blink Code Output:
- If you choose to use mode 02, Blink Code Output, skip to Step 10.
Select mode 01, Rapid Data Transfer, and address word 01. Now press the 0 button to enter your selection. The tester will display a control unit part number, the system it controls and an application (country) code.
- If the information is displayed and is correct, press the (run) key to continue. The display 'Select function XX' will appear.
- If 'Control unit does not answer' is displayed, use the Help key to display a list of possible causes. When the problem is repaired, return to step 1 and start over again.
- When function 02 is selected, the control module will report fault codes to the diagnostic tester.
- When all codes have been reported, proceed to the Output Check diagnosis or select function 06 to exit the fault code memory without erasing the codes. Repair and erase the faults, then check and see if all faults have been corrected.
- The following steps will retrieve engine codes by using Blink Code Output.
- To operate the VAG 1551 tester in Blink Code Output, select menu option # 2. An asterisk will appear and flash the codes, which the tester will count and report on the screen as numbers. If Code 4444 or 0000 is displayed, no faults are found in memory.
- If the engine is not running, some codes may be displayed. These can be ignored if the engine was intentionally stalled, but should be investigated if the engine will not start.
- Press the (run) key to advance to the next code. Read through entire code list before starting repairs.
- When the 0000 (output ended) code is displayed, pressing the (run) key again will proceed to another control module. If no other control modules are to be tested, the following display will appear: Blink Code Output is ended. To stop the program without erasing the codes, turn the ignition key OFF and press the clear C button once.
- Repair and erase the faults, then check to see if all faults have been corrected.
Only the Motronic system is equipped with this program. It allows testing most of the engine output devices without running the engine. The program cannot be run without the VAG 1551 Diagnostic Tester or equivalent. During the test, four output devices are activated in the following order:
Testing the differential pressure regulator requires a multi-meter that will read milliamps. The other items can be checked with a voltmeter, test light or by listening and feeling for valve activation. The cold start valve is activated for a limited time to avoid flooding the engine.
- Connect the diagnostic tester, turn the ignition switch ON and confirm that the tester will communicate with the control unit. See the procedure for retrieving fault codes.
- Select Rapid Data Transfer and Function 03. When the test is started by pressing the Q button (enter), the first output signal is generated.
- Each time the Run button is pressed, the tester will send an output signal to the next device on the list.
- When the last item has been tested, select Function 06 to exit the program. To repeat the test, turn the ignition switch OFF and ON again.