Low Fuel Pressure Sensor, Checking

Low Fuel Pressure Sensor, Checking

Special tools, testers and auxiliary items required

• Multimeter

• wiring diagram

Test requirements

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

• The fuel filter OK.

• The fuses for the engine electronics OK.

• The parking brake engaged.

• The battery voltage at least 12.5 V.

• The selector lever of automatic transmission in position "P" or "N".

• 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

Procedure

- Remove the engine cover with air filter - 1 -. Refer to appropriate service manual.





Checking voltage

- Disconnect the electrical harness connector - 2 - from the Low Fuel Pressure Sensor (G410).





- Switch the ignition on.

- Using a Multimeter , check the electrical harness connector for voltage.










- Switch the ignition off.

If specified value is obtained:

- Replace the Low Fuel Pressure Sensor (G410)

If the specified value was not obtained:

Checking wiring connections

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 Engine Control Module (ECM) (J623). Refer to appropriate service manual.










Specified resistance 1.5 ohms max.

If the specification is not obtained:

- Check the wiring for a short circuit to Battery positive (+) or an open circuit.

- If necessary, repair the wiring connection.

- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09

- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.

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 appropriate service manual.

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

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

3. If the DTC memory was erased, generate readiness code. => [ Readiness Code ] Programming and Relearning.