Safety Precautions When Working on the Fuel Supply System
Motronic Multiport Fuel Injection (MFI) System, Servicing
Safety Precautions
WARNING!
Be alert when working on or near the engine. High ignition secondary voltage can cause serious personal injury and damage vehicle components.
- DO NOT touch or disconnect ignition system wires when the engine is running or being cranked at starting RPM.
- DO NOT operate the starter if fuel injectors are removed.
Be sure the ignition is switched OFF, when:
- Disconnecting ignition wires or fuel injection wiring
- Connecting or disconnecting test equipment leads
- Disconnecting the battery
- Washing the engine or engine compartment.
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 03.
- 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.