Fuel Pump, Checking

Fuel Pump, Checking

Special tools, testers and auxiliary items required

• Pressure Tester (VAS 6550)

• Remote Control (V.A.G 1348/3A)

• Test Instrument Adapter/DSO (5-pin) (VAS 5565)

• Multi-meter (V.A.G 1715)

• Wrench (T10202)

• Torque Wrench (40-200 Nm) (V.A.G 1332)

• Measuring Container, 2 Liter

Function and Voltage Supply, Checking

Test Conditions:

• Battery voltage at least 11.5 volts.

• Fuel pump control module (J538) fuse is OK

• Fuel pump control module is OK

Test Sequence:

• Fuel pump function is checked via the output Diagnostic Test Mode (DTM).

- Connect the vehicle diagnostic tester as follows:





- Connect the diagnostic cable connector to the Data Link Connector (DLC) in the driver's footwell.

- Turn on the ignition.

- Press the Vehicle Self-Diagnosis, Engine Electronics and Output Diagnostic Test Mode buttons on the display.

- Press the right arrow button ► on the display until output diagnostic test mode for the fuel pump electronics is reached.

Fuel pump must now accelerate slowly up to maximum RPM.

• Fuel pump runs quietly.

- Turn off the ignition.

If the Fuel Pump does not Start:

- Remove the rear seat bench.

- Disconnect the connector from the fuel pump control module.





- Check the voltage supply between terminals - 1 and 6 - using (V.A.G 1715).





• Specified value: approximately battery voltage

Voltage Supply not OK:

- Locate and repair the open circuit in the wiring using the wiring diagram.

Voltage Supply OK:

- Remove the cover - 1 - with fuel pump control module - 2 - from the fuel delivery unit.





- First, pull on the connector - arrow - without pressing the retainer to make sure it is connected securely. If the connector was not connected correctly, check the fuel pump function again.





- Disconnect the connector.

- Check the contacts on the connector and the fuel delivery unit for damage.


The fuel supply line is under pressure! Wear protective goggles and protective clothing to prevent injuries and contact with skin. Before disconnecting the connection, wrap a cloth around the connection. Then, disconnect the connection carefully to release the pressure.

- Remove the fuel lines - 1 and 2 - from the flange.





• Press in the securing ring to disengage the fuel lines.

- Remove the lock ring using wrench (T10202).





- Check whether the electrical wires between the flange and fuel pump are connected.

If No Open Circuits are Found:

- Replace the fuel delivery unit, the fuel pump is faulty. Refer to => [ Fuel Delivery Unit ] Fuel System Components.