Fuel Pump Control Module, Checking

Special tools and workshop equipment required 

• multimeter
• Wiring diagram.

Test conditions 

• Fuse -SC3- 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 requirements 

-- Perform a preliminary check to verify the customer's complaint. Refer to 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 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 T5e/1, black 5 pin connector, for resistance.

Specified value: 1.5 Ω 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 .

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 .
2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .