Fuel Pressure Regulator Valve, Checking

Fuel Pressure Regulator Valve, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• Fuse (SB11) 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.

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).

If the specified value was obtained:

Checking voltage

- Crank the engine.

- 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) socket 2/87 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.

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

- Remove the Motronic Engine Control Module (ECM) (J220). Refer to => [ Engine Control Module ] Engine Control Module.

- Using a multimeter, check the Fuel Pressure Regulator Valve (N276) electrical harness connector terminal to the Motronic Engine Control Module (ECM) (J220) electrical harness connector T60 terminal for an open circuit.









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 ] Diagnostic Mode 04 - Erase DTC Memory.

- Perform a road test to verify repair.

If the DTC does not return:

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

- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was not OK:

- Replace the Motronic Engine Control Module (ECM) (J220). Refer to => [ Engine Control Module ] Engine Control Module.

After the repair work, the following work steps must be performed in the following sequence:

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.