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7.7 Digifant II On-Board Fault Diagnosis (California only)

Some cars equipped with the Digifant II engine management system and delivered for sale in California are equipped with an on-board diagnosis (OBD) system as part of the Digifant II electronic control unit. The OBD system detects faults in the engine management system (fuel and ignition) and them reports them through a combination rocker switch/indicator light, located at the right of the instrument panel. See Fig. 7-23.

Fig. 7-23. Combination rocker switch/indicator light at right of instrument panel serves as readout for Digifant II on-board diagnosis (OBD) system (California cars only).

When operating properly, the light should come on once, briefly, when the ignition is turned on. The light will also come on after a short period of driving to report any faults in the engine management system.

To display the fault code, turn the ignition on (DO NOT start the engine) and depress the rocker switch for at least four seconds. The indicator will display the fault code in a series of flashes. For example, two flashes, followed by three flashes, followed by four flashes, followed by two flashes indicates the code 2-3-4-2. Table r gives a complete list of available fault codes.

Possible wiring faults should be checked and corrected before replacing a suspected component. To retest after a repair it will be necessary to erase the fault memory as described below and then drive the car again for at least 10 minutes.

Table r. Digifant II On-Board Diagnosis (OBD) Fault Codes (California only)

To erase fault code memory:
1. Make sure the ignition is switched off.
2. Depress and hold the rocker switch. With the switch depressed, turn the ignition on.
3. Keep the switch depressed for at least 5 seconds. Then turn the ignition off.
4. Test drive the car for at least 10 minutes.


Not all California models are equipped with the fault diagnosis system, and there are some variations among those which are so-equipped. The publisher recommends consulting with an authorized Volkswagen dealer for the most accurate and up-to-date information about a particular car.

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