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8. Digifant I Fuel Injection (California)

The Digifant I engine management system is a further development of the Digifant II engine management system. Digifant I is installed on California 8-valve models (engine code RV) beginning in 1991.

The basic design and operation of Digifant I is the same as Digifant II, where the engine's ignition and fuel injection functions are combined into one system to be managed by a single electronic control unit. Digifant I and Digifant II share many of the same components and functions. The following are the significant differences of Digifant I:

A control unit with expanded fault memory capability and functions, including adaptive learning for fuel mixture and idle speed, and communication capability (rapid data transfer) between the control unit and Volkswagen special tool 1551

A throttle valve potentiometer to signal throttle position, replacing dle and full-throttle switches

Simpler idle speed and mixture adjustment procedures

An ignition coil with a power stage

This heading covers only those Digifant I components and functions that are different from Digifant II. For a more thorough description of the design and operation of the Digifant engine management system, see 7. Digifant II Fuel Injection. For a discussion of the ignition functions of Digifant I, see IGNITION.

Although dealership technicians use special equipment to service the Digifant I system, it has been designed so that almost all electrical components can be tested using only a low-current LED test light and a multimeter. Most of these tests can be performed right at the Digifant I control unit harness connector. The only other major piece of test equipment required is a fuel pressure gauge. Incorrect system fuel pressure can directly affect engine performance.


Always turn the ignition off before disconnecting or connecting the Digifant I control unit connector or any test equipment. Doing so with the ignition on risks ruining the control unit.

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