Fuel Pressure Regulator Valve N276, Checking

Diagnostic Procedures

Fuel Pressure Regulator Valve N276, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• Fuse (SB33) 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

- Observe safety precautions. Refer to => [ Safety Precautions ] Safety Precautions

- Observe Clean Working Conditions. Refer to => [ Clean Working Conditions ] Clean Working Conditions

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

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: 1 to 5 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

- Start the engine.

- Using a multimeter, check the Fuel Pressure Regulator Valve (N276) electrical connector terminal 1 to ground 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 fuse 7 in Fuse Panel B for high resistance, a short circuit to voltage, ground, or an open circuit.

- Check the electrical harness connector for damage, corrosion, loose 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) (J623). Refer to the Repair Information.

- Using a multimeter, check the Fuel Pressure Regulator Valve (N276) electrical harness connector terminal to the Motronic Engine Control Module (ECM) (J623) 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 an open, high resistance or short circuit to voltage or ground.

- Check the electrical harness connector for damage, corrosion, loose 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 Modes 01 - 09.

- Perform a road test to verify repair.

If the DTC does not return:

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

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

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to the Repair Information.

- 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 Modes 01 - 09.

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

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