Fuel Pump (FP) Delivery Quantity, Checking

Fuel Pump (FP) delivery quantity, checking

Special tools, testers and auxiliary items required

• Hand held remote control (jumper).

• Multimeter.

• Electrical connector test lead set.

• Fuel pressure test set (high pressure).

• Measuring container, fuel-resistant.

Test conditions

• Fuse (SD12) OK.

• Fuse (SF6) OK.

• Fuse (SC1) OK.

• Fuel Pump (FP) Control Module (J538)

• Battery voltage 12.5 V

• Fuel filter OK

• Fuel tank at least 1/4 filled.

• Fuel pressure regulator OK.

• Ignition switched off.

Test sequence

- Remove the fuel filler cap from fuel filler tube.

TT Coupe

- Remove the rear seat bench.

TT Roadster

- Remove the right rear side trim panel.

All vehicles

- Remove cover retainers - arrows - from the right sealing flange.





- Disconnect the electrical harness connector - arrow - from the fuel delivery unit.





- Connect a Hand held remote control (jumper) to terminal - 1 - of the fuel delivery unit and to vehicle battery (+).

- Connect a jumper cable from a Electrical connector test lead set to terminal - 5 - of the fuel delivery unit and to vehicle Ground (GND).





- Disconnect the fuel line from the bracket and remove the heat shield - arrow -.





Fuel system is under pressure! Before opening the system, place rags around the connection area. Then release the pressure by carefully loosening the connection.

- Disconnect the fuel return line - arrow - by pulling the release ring.

- Connect a fuel line from the Fuel pressure test set (high pressure) to the disconnected fuel return line and hold it in the measuring container - arrow -.





- Press the switch on the Hand held remote control (jumper) and slowly close the shut-off valve of the fuel pressure gauge.

- Specified value: 6 Bar positive pressure.

- With the shut-off valve of the fuel pressure gauge in the same position.

- Empty measuring container.

- Press the switch on the Hand held remote control (jumper) and operate the fuel pump for 15 seconds.

- Compare quantity of fuel delivered with minimum delivery rate in the diagram (cm3/15s).





• Voltage at the fuel pump with engine stopped and fuel pump running is approx. 2 volts less than battery voltage.

If minimum delivery quantity is not obtained, the following malfunctions may be present:

• Fuel lines pinched.

• Fuel filter plugged.

• Fuel pump faulty.

- If necessary, repair any pinched or plugged lines.

- Replace the fuel filter.

- Replace the fuel pump.

Assembly is performed in reverse order of removal.

Final procedures

After the repair work, the following work steps must be performed in the following sequence:

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Engine.

End of diagnosis