Fuel injection System

Safety Precautions


• Fuel system is under high pressure! Before opening high pressure components of the fuel injection system, pressure must be relieved to residual pressure. Refer to => [ Before Opening High Pressure Fuel Injection System ] Service and Repair.

• Then wrap a clean rag around the connection and relieve residual pressure by carefully loosening the connection.

Observe the following if test and measuring instruments are required during a test drive:


Distraction and improperly secured test equipment can lead to accidents.

Risk of passenger airbag deploying in an accident.

• Operating testing and measuring equipment while driving creates a distraction.

• There is an increased risk of injury due to unsecured testing and measuring equipment.

• Always secure testers on the rear seat with a strap and have a second person on the rear seat operate them.

To reduce the risk of personal injury and/or damage to the fuel injection and ignition system, always observe the following:


• The battery must only be disconnected and connected with the ignition switched off, since the Engine Control Module (ECM) can otherwise be damaged.

• Observe safety precautions when disconnecting the battery.

• For safety reasons, if the battery is not disconnected, Fuel Pump (FP) Control Module (J538) fuse must be removed before opening fuel system. Otherwise, the fuel pump will be activated by the driver's door contact switch.





• Individuals with a pacemaker must not stay in the danger area of high voltage systems, e.g. ignition systems, xenon light.

• Fuel lines must not be opened when engine is running.

• Only disconnect and reconnect wires for injection and ignition system, including test leads, when ignition is switched off.

• If engine is to be cranked at starting RPM without starting (e.g. for compression testing), disconnect connectors from ignition coils and remove fuse for electric fuel pump.

• It is possible that the control module will recognize a malfunction and store a DTC during some tests. Therefore after completing all checks and repairs the DTC memory must be checked and if necessary erased.

• Cleaning the engine should only be performed with ignition switched off.

• The battery must only be disconnected and connected with the ignition switched off, since the ECM can otherwise be damaged.