Multiport Fuel Injection

Safety Precautions

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.


Fuel system is under pressure! Fuel pressure must be reduced to a residual pressure before opening high pressure area of injection system. Refer to => [ Before Opening High Pressure Fuel Injection System ] Service and Repair.

After reducing high pressure, connection should be opened immediately. To do this, place a cloth around the connection to reduce residual pressure (approximately 6 bar).

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

• For safety reasons, if the battery is not disconnected, fuse SC 27 from the fuel pump control module (J538) must be removed before opening the 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, for example 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 (for example 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.

• If the DTC memory was erased, the readiness code must be newly generated.

• 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 engine control module (ECM) can otherwise be damaged.

• If engine is to be cranked at starting RPM without starting (for example for compression testing), disconnect the four connectors for ignition coils, using the ignition coil puller (T40039). Refer to => [ Ignition Coils with Power Output Stages ] Service and Repair. Also remove fuse SC 27 from fuel pump control module (J538).





• By removing fuse SC 27, the voltage supply to terminal 30 for the fuel pump control module is interrupted.