Auxiliary Fuel Pump Relay

Auxiliary Fuel Pump Relay

Observe all safety precautions: => [ Safety Precautions ] Safety Precautions

View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions

Prior to repair work, perform a preliminary check to verify the condition. Refer to => [ Preliminary Check ] Preliminary Check.

Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.

Special tools, testers and auxiliary items required

• Multimeter

• Wiring diagram

Test requirements

• The engine control module fuses OK

• Battery voltage at least 12.5 volts

• All electrical consumers switched off

• Vehicles with automatic transmission, shift selector lever in park or neutral

• A/C switched off

• Ground connections between engine/transmission/chassis OK

• Ignition switched off

Test procedure

- Remove the Auxiliary Fuel Pump Relay (J832).

Checking the supply voltage

- Turn the ignition switch ON

- Using a multimeter, measure the voltage of the Auxiliary Fuel Pump relay circuit (socket 32).

Specified value: battery voltage.

- Turn the ignition switch OFF

If the specified value was not obtained:

- Check the power supply circuit between the Auxiliary Fuel Pump Relay (J832)and fuse SC27 for an open circuit or a short circuit.

- Check the wiring connections for damage, corrosion, loose or broken terminals.

- Repair as necessary.

- Turn the ignition switch ON

- Using a multimeter, measure the voltage of the Auxiliary Fuel Pump Relay (J832) (socket 42).

Specified value: battery voltage.

- Turn the ignition switch OFF

If the specified value was not obtained:

- Replace the Auxiliary Fuel Pump Relay (J832).

If the specified value was obtained:

- Check the wiring connections for damage, corrosion, loose or broken terminals.

Checking wiring

- Remove the engine control module. Refer to the service information for procedures.

- Using a multimeter, measure the resistance of the circuit between the Auxiliary Fuel Pump Relay (J832) and the engine control module Engine Control Module (ECM) (J623).






Specified value: 1.5 ohms Max.

If the specification was not obtained:

- Check the wires for a short circuit to each other, a short to battery voltage, and a short to ground.

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

- Repair as necessary.

If no malfunction is found in the wiring and voltage supply was OK:

- Replace the engine control module Motronic Engine Control Module (ECM) (J623).

Final procedures

After 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 - 0A.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 0A.

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