Fuel Pressure Sensor, Checking

Diagnostic Procedures

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 Motronic 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 engine cover with air filter. Refer to the repair information.

Checking voltage

- Disconnect the Fuel Pressure Sensor (G247) electrical harness connector.

- Switch the ignition ON.

- Using a multimeter, check the Fuel Pressure Sensor (G247) electrical harness connector - 1 - terminals for voltage.









- Switch the ignition OFF.

If the specified value was obtained:

- Replace the Fuel Pressure Sensor (G247): Refer to the repair information.

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 Motronic Engine Control Module (ECM) ( J623). Refer to the repair information.

- Using a multimeter, check the Fuel Pressure Sensor (G247) harness connector terminals to the Motronic Engine Control Module (ECM) (J623) harness connector for an open circuit according to the chart below.





Specified value: 1.5 ohms Max.

If the specified value was Not obtained:

- Check the wiring for an open, high resistance or short to ground.

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

- If necessary, repair the faulty wiring connection.

If the specified value was obtained:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to the repair information.

- Install the engine cover with air filter. Refer to the repair information.

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 ] Scan Tool Testing and Procedures.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Scan Tool Testing and Procedures.

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