Control Unit

NOTE: Control units are known to be the cause of various customer DRIVEABILITY complaints. Various campaigns which may include control unit replacement, and system modifications have been implemented by Volkswagen to remedy this situation. Always refer to TECHNICAL SERVICE BULLETINS for the latest information concerning DRIVING PERFORMANCE.

If a problem is not remedied after completing the test procedures in SYSTEM ELECTRICAL TESTS, the control unit may be found to be defective. Replace the control unit with a known good unit and retest as necessary.

CAUTION: Always turn the ignition switch "OFF" before changing meter ranges, and before disconnecting or connecting the meter probes. Doing so with the ignition switch turned "ON" risks permanent control unit damage.

NOTE: Because of its adaptive capability, the Digifant I control unit MUST be returned to its reference settings IF:

1. The coolant temperature sensor (blue connector) has been disconnected while the engine is running.

2. Any of these components have been replaced:
^ Digifant I control unit
^ Air flow sensor
^ Throttle valve potentiometer
^ Throttle body

Programming and Relearning