Fuel Delivery and Air Induction: Description and Operation

Fuel Injection System


The fuel system is under pressure!

• Before opening the high pressure components of the fuel injection system, the fuel pressure must be relieved to residual pressure, refer to => [ High Side Fuel Pressure, Releasing ] Service and Repair.

• The Engine Control Module (ECM) is equipped with On Board Diagnostic (OBD). Before repairs such as fault finding, check the Diagnostic Trouble Code (DTC) memory first using "Guided Function" in the vehicle diagnostic tester. Also the vacuum hoses and connections must be checked (unmetered air).

• For the electric components to work properly, a voltage of at least 12 volts is required.

• Do not use sealants containing silicone. Particles of silicone drawn into the engine, will not be burnt in the engine and will damage the oxygen sensor.

• The vehicles have a crash fuel shut off. It reduces the danger of a fire in a crash as the fuel pump is switched off via the fuel pump relay.

• This setup also makes it easier to start the engine. When the drivers side door is opened, the fuel pump is activated for 2 seconds so that pressure builds in the fuel system, observe the safety measures. Refer to => [ Safety Precautions ] Fuel Supply.

• Fuel hoses in the engine compartment must only be secured with spring-type clips. The use of clamp or screw type clips is not permissible.

• Install only approved clamps for securing hose connections.

• Use spring-type clip pliers to installing spring clips.

• To conclude work, check the DTC memory of the ECM, erase all DTC entries which may have occurred during the tests and repairs. If the DTC memory was erased, the readiness code must be generated again, refer to "Guided Fault Finding" in the vehicle diagnostic tester.

• If the engine only starts briefly and then shuts off again after troubleshooting, repairs or checking of the components, it may be that the immobilizer is blocking the ECM. The control module may have to be adapted then, refer to "Guided Functions" in the vehicle diagnostic tester.