Ignition System: Service 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 the fuel injectors have been removed.

BE Sure The Ignition Is Switched OFF, When:
- Disconnecting Ignition Wires
- Disconnecting fuel injection system wiring
- Connecting or disconnecting test equipment leads
- Disconnecting the battery
- Washing the engine or engine compartment.

BEFORE Cranking The Engine At Starting RPM, disable the ignition and fuel injection systems:
- Disconnect the ignition coil power output stage.
- Disconnect harness connectors from all fuel injectors.
- After the work is completed, clear Diagnostic Trouble Code memory.

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.
- 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:
- 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.
- To prevent damage to electronic components, switch multi-meter to correct measuring range before connecting the adapter cable. Observe test conditions and carry out additional work listed in the table.