Fuel Injection System, Servicing

Safety Precautions

To reduce the risk of personal injury and/or damage to the fuel injection and ignition system, always observe the following:
- Always switch off ignition before disconnecting or connecting lines of the fuel injection and ignition system, including test leads.
- If engine is to be cranked at starting RPM without starting (e.g. for compression testing), remove fuse 28 from the fuse carrier and disconnect connectors from ignition coils with assembly tool T10118.
- During some of the tests, a fault may be recognized and stored by the control module. At the end of all tests and repairs, the fault memory should be checked and, if necessary, erased.
- Always switch ignition off before cleaning engine.
- Always witch off the ignition before connecting or disconnecting the battery or the engine control module may be damaged.

WARNING: The fuel system is under pressure. Place a cloth around the connection before opening the system. Then relieve pressure by carefully loosening the connection.

Note the following if testers and measuring instruments have to be used during a road test:

CAUTION:
- To avoid risk of accident, observe the following precautions when using test instruments while road testing the vehicle:

Audi TT Coupe:
- To read measured value blocks, use only the vehicle diagnostic, testing and information system VAS 5051 A or the vehicle diagnostic and information system VAS 5052. Test equipment must always be secured on the rear seat and operated from that position by a second person.
- Due to the limited space available, the front passenger's seat is to be moved forward as far as it will go and the engaged backrest folded forward as far as it will go with the backrest adjuster handwheel. Do not operated the release lever to tilt the backrest forward.

Audi TT Roadster:
- In the Audi TT Roadster, only use the vehicle diagnostic and information system VAS 5052 with the passenger's airbag deactivated.
- Deactivate the front passenger's airbag via the key switch in the glove box or the self-diagnosis.
- Reactivate the front passenger's airbag upon completion of work.