Motronic Multiport Fuel Injection (MFI) System Servicing

BEFORE cranking the engine at starting RPM (as for compression test) disable ignition and fuel injection systems:
- Disconnect both ignition coil power output stages, and both fuses for Motronic in the E-box in the plenum.
- After the work is completed, erase Diagnostic Trouble Code (DTC) memory, and carry out component functional checks using "Output Diagnostic Test Mode" function 08.
- If necessary, correct any malfunctions, erase DTC memory and generate new readiness code.

CAUTION: BEFORE disconnecting the battery:
- Stop the engine.
- Be sure the ignition is switched OFF (also applies when connecting the battery). Failure to do so may damage the Engine Control Module (ECM).
- Be sure of the proper radio code (for vehicles equipped with coded anti-theft radio).

Be sure the battery negative (-) cable is disconnected, when:
- Working on the electrical system
- Resistance (spot) welding or electric arc welding anywhere on the vehicle.

When connecting and disconnecting electrical test equipment (LED voltage tester multimeter, etc.):
- Be sure the ignition is switched OFF
- Use correct adapters from the VW 1594 connector test kit For any work affecting the Engine Control Module (ECM):
- BEFORE disconnecting the ECM harness connector switch the ignition OFF and WAIT at least 20 seconds. Failure to do so may damage the ECM.
- DO NOT connect any outside voltage source to stimulate an output signal at the ECM.