Fuel Pressure Regulator Valve, Checking
Fuel Pressure Regulator Valve, Checking
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• The Engine Component Power Supply Relay (J757) 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. Refer to the appropriate service manual.
- Disconnect the connector -1- from the Mass airflow sensor (G70) , and remove the Air Filter Housing. Refer to appropriate service manual.
Checking resistance
- Disconnect the Fuel Pressure Regulator Valve (N276) electrical harness connector - 1 -.
- 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 the appropriate service manual
- Go to Final procedures
If the specified value was obtained:
Checking voltage
- Switch the ignition ON.
- Using a Multimeter, check the Fuel Pressure Regulator Valve (N276) electrical harness 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 harness connector terminal 1 to Fuse (SB 5) in Fuse Panel B for an open circuit or a short circuit to Ground (GND).
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- If necessary, repair the faulty wiring connection.
- Repair the circuit and replace any open fuses.
- Go to Final procedures
If the specified value was obtained:
Checking wiring connections
- Remove the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.
- Using a Multimeter, check the Fuel Pressure Regulator Valve (N276) electrical harness connector terminal 2 to the Engine Control Module (ECM) (J623) electrical harness connector T60 terminal 60 for resistance.
Specified value: 1.5 ohms Max.
If the specified value was Not obtained:
- Check the wiring for an open circuit, a short circuit to each other, Battery voltage or Ground (GND).
- If necessary, repair the faulty wiring connection.
- Go to Final procedures
If the specified value was obtained:
- Erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 0A
- 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.
- End diagnosis.
If the DTC returns and no malfunction is found in the wiring and voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) (J623). Refer to appropriate service manual.
Final procedures
- Reinstall the engine cover and air filter housing, if necessary. Refer to the appropriate service manual.
- 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 Modes 01 - 0A.
2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 0A.
3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.