Transfer Fuel Pump, Electrical Checking

Transfer Fuel Pump, Electrical Checking

Special tools, testers and auxiliary items required
- Hand held remote control (jumper).
- Multimeter.
- Electrical connector test lead set.

Test conditions
- Battery voltage 12.5 V.
- Fuse S228 OK.
- Motronic Engine Control Module (ECM) Power Supply Relay J271 OK.
- Fuel Pump (FP) Control Module J538 OK.
- Fuel filter OK.
- Ignition switched off.

Test sequence
- Remove the rear seat bench.







- Remove the left locking flange cover - arrows -.







- Disconnect the Transfer Fuel Pump (FP) G6 electrical harness connector - arrow -.







- Connect a Hand held remote control (jumper) to terminal - 1 - of the Transfer Fuel Pump (FP) G6 and to vehicle battery (+).
- Connect a jumper cable from a Electrical connector test lead set to terminal - 4 - of the Transfer Fuel Pump (FP) G6 and to vehicle Ground (GND).
- Press the switch on the Hand held remote control (jumper).

NOTE: The Fuel Pump (FP) runs quietly. Avoid surrounding noises while testing the fuel pump.

- Listen for an operating noise from the Transfer Fuel Pump (FP) G6.

If no operating noise is heard:
- Remove the fuel delivery unit.







- Using a Multimeter , check the Transfer Fuel Pump (FP) G6 electrical terminals 1 to 4 for continuity.

Specified value: 0 Ohm.

If the specification was not obtained:
- Check the Transfer Fuel Pump (FP) G6 electrical harness connector terminal 1 to 4 for a short circuit to Battery positive (+) or an open circuit.
- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring and the resistance value was not OK:
- Replace the fuel pump.

If no malfunction is detected in the wiring and the resistance value was OK:

If an operating noise is heard:

Checking voltage
- Switch the ignition on.
- Using a Multimeter , check the Transfer Fuel Pump (FP) G6 electrical harness connector terminal 1 to Ground (GND) for voltage.
- Switch the ignition off.

Specified value: Battery voltage.

If the specification was not obtained:
- Check the Transfer Fuel Pump (FP) G6 electrical harness connector terminal 1 to the Fuel Pump (FP) Control Module J538 electrical harness connector terminal 1 for an open circuit, or a short circuit to Battery positive (+) or Ground (GND).
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.

If the specification was obtained:

Checking Ground (GND)
- Using a Multimeter , check the Transfer Fuel Pump (FP) G6 electrical harness connector terminal 4 to the Fuel Pump (FP) Control Module J538 electrical harness connector terminal 2 for resistance.

Specified value: 1.5. Ohms Max.

If the specification was not obtained:
- Check the Transfer Fuel Pump (FP) G6 electrical harness connector terminal 4 to the Fuel Pump (FP) Control Module J538 electrical harness connector terminal 2 for an open circuit, or a short circuit to Battery positive (+) or Ground (GND).
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:
- Replace the Fuel Pump (FP) Control Module J538.
- Assembly is performed in the reverse of the removal.

Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

- End of diagnosis