Fuel Pump Control Module, Checking

Fuel Pump Control Module, Checking

Special tools, testers and auxiliary items required

• multimeter

• Wiring diagram.

Test requirements

• Fuse (SC1) OK.

• Battery voltage at least 12.5 volts.

• All electrical consumers such as, lights and rear window defroster, switched off.

• Vehicles with automatic transmission, selector lever in position "P" or "N".

• A/C switched off.

• Ground (GND) connections between engine/transmission/chassis OK.

• Ignition switched off.

Test procedure

- Perform a preliminary check to verify the customer's complaint. Refer to => [ Preliminary Check ] Preliminary Check

Start diagnosis

- Remove rear seat assembly. Refer to the appropriate service information.

Checking voltage

Switch the ignition on.

- Using a multimeter, check the following wiring connection for voltage.





Specified value: Battery voltage

- Switch the ignition off.

If the specified value was not obtained:

- Check the Fuel Pump (FP) Control Module (J538) wiring harness terminal 3 to the Motronic Engine Control Module (ECM) Power Supply Relay (J271) terminal 8/87 for an open circuit or short to Ground (GND).

- Check the electrical harness connectors for damage, corrosion, loose or broken terminals.

- If necessary, repair the wiring connection.

Checking Ground (GND)

- Using a multimeter, check the Fuel Pump (FP) Control Module (J538) wiring harness terminal 1 to T5a/1, black 5 pin connector, for resistance.





Specified value: 1.5 ohms maximum.

If the specified value was not obtained:

- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring and the voltage supply was OK:

- Replace the Fuel Pump (FP) Control Module (J538). Refer to the appropriate service information.

- Perform a road test to verify repair.

If the fault does not return:

Generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

If the fault does return and no malfunction is detected in the wiring and the voltage supply was OK:

- Replace the Engine Control Module (ECM) (J623). Refer to the appropriate service information.

- 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. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.