Low Fuel Pressure Sensor, Checking

Low Fuel Pressure Sensor, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Fuel Pump (FP) Control Module (J538) OK.

• The Engine Control Module (ECM) (J623) fuses OK.

• The fuel filter OK.

• The battery voltage at least 12.5 V.

• All electrical consumers switched off (radiator fan must NOT run during test).

• A/C switched off.

• The fuel tank at least 1/4 filled.

• The ignition switched off.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to --> [ Preliminary Check ] Preliminary Check.

Start diagnosis

- Remove the rear engine cover - arrows -.





Checking voltage

- Disconnect the Low Fuel Pressure Sensor (G410) connector.

- Switch the ignition on.

- Using a multimeter, check the Low Fuel Pressure Sensor (G410) electrical harness connector for voltage.









- Switch the ignition off.

If the specified values are obtained:

- Replace the Low Fuel Pressure Sensor (G410), note the following:

If the specified values are not obtained:

Checking wiring

If the manufacturers test box is being used. Perform the following step.

- Install the test box.

If the manufacturers test box is not being used. Perform the following step.

- Remove the Motronic Engine Control Module (ECM) (J623). Refer to --> [ Engine Control Module, Replacing ] Engine Control Module, Replacing.

- Using a Multimeter, check the Low Fuel Pressure Sensor (G410) electrical harness connector terminals to the Engine Control Module (ECM) (J623) electrical harness connector T94 terminals for an open circuit according to the wiring diagram.









Specified value: 1.5 ohms Max.

If the specification was not obtained:

- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).

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

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

- Erase the DTC memory. Refer to --> [ Diagnostic Mode 04 - Erase DTC Memory ] Clearing Diagnostic Trouble Codes.

- Perform a road test to verify repair.

If the DTC does not return:

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

- End diagnosis.

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

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to --> [ Engine Control Module, Replacing ] Engine Control Module, Replacing.

- Assembly is performed in the reverse of the removal.

Final procedures

After repair work, the following work steps must be performed in the mentioned 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 ] Clearing Diagnostic Trouble Codes.

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