Fuel Injection System

Safety Precautions

If special testing equipment is required during a road test, note the following:


Distraction and improperly secured test equipment can lead to accidents.

There is a risk that the passenger airbag could deploy in a collision.

• 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 safety belt 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:


• Fuel system is under high pressure! The pressure must be reduced to residual pressure before opening the high pressure components of the fuel injection system. 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.


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

• Observe safety precautions when disconnecting the battery.

• For safety reasons, remove fuse - SC 1 - in relay and fuse holder, at right of instrument panel from the Fuel Pump Control Module (J538) before opening the fuel system if the battery is not disconnected, because the driver door contact switch activates the fuel pump.





• Individuals with a pacemaker must not stay in the danger area of high voltage systems, for example ignition system, 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, for example, for a compression test, disconnect the connector from the ignition coils and remove the fuse from the 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 is switched off, since the Engine Control Module (ECM) can otherwise be damaged.