Fuel Pressure Regulator Valve, Checking

Fuel Pressure Regulator Valve, 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) (J220) 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 repair information.

Checking resistance

- Disconnect the Fuel Pressure Regulator Valve (N276) electrical harness connector - 2 -.





- Using a Multimeter, check the Fuel Pressure Regulator Valve (N276) terminals 1 to 2 for resistance.





Specified value: 25 to 35 ohms (at approx. 20 °C)

If the specified value was not obtained:

- Replace the Fuel Pressure Regulator Valve (N276): Refer to repair information.

If the specified value was obtained:

Checking voltage

Switch the ignition on.

- Using a Multimeter, check the Fuel Pressure Regulator Valve (N276)electrical connector terminal 1 to Ground (GND) for voltage.





Specified value: battery voltage.

Switch the ignition off.

If the specified value was not obtained:

- Check the wiring from the Fuel Pressure Regulator Valve (N276) electrical connector terminal 1 to the Engine Component Power Supply Relay (J757) terminal 2 for a short circuit to Battery positive (+), Ground (GND), or an open circuit.

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

- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking wiring

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

- Install the test box. Refer to repair information.

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

- Remove the Motronic Engine Control Module (ECM) (J220).

- Using a Multimeter, check the Fuel Pressure Regulator Valve (N276) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J220) electrical harness connector T60 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:

- Replace the Motronic Engine Control Module (ECM) (J220). Refer to repair information.

- Install the engine cover with air filter. Refer to 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 ] Diagnostic Mode 03 - Read DTC Memory.

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

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