Fuel Pressure Regulator Valve Checking
Fuel Pressure Regulator Valve Checking
Observe all safety precautions: => [ Safety Precautions ] Safety Precautions
View clean working conditions: => [ Clean Working Conditions ] Clean Working Conditions
Prior to repair work, perform a preliminary check to verify the condition. Refer to => [ Preliminary Check ] Preliminary Check.
Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.
For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.
Special tools, testers and auxiliary items required
• Multimeter
• Wiring diagram
Test requirements
• The Engine Speed (RPM) Sensor (G28) OK.
• Battery voltage at least 12.5 volts.
• All electrical consumers such as, lights and rear window defroster, switched off.
• Vehicles with automatic transmission, shift selector lever into position "P" or "N".
• A/C switched off.
• Ground connections between engine/transmission/chassis OK.
• Ignition switched off.
Start diagnosis
- Remove the engine cover.
- Disconnect the Fuel Pressure Regulator Valve (N276) electrical harness connector.
Checking internal resistance
- Using a multimeter, check the Fuel Pressure Regulator Valve (N276) terminals 1 to 2 for resistance.
Specified value: Near 4.1 ohms (at approx. 20° C)
If the specified value was Not obtained:
- Replace the Fuel Pressure Regulator Valve (N276). Refer to the repair information.
If the specified value was obtained:
- Turn the ignition switch ON.
- Connect a multimeter red lead to terminal 2 of the Fuel Pressure Regulator Valve (N276) and the other meter lead to ground and measure the voltage.
- Turn the ignition switch OFF.
Specified value: Battery voltage.
If the specified value was Not obtained:
- Check the circuit between terminal 2 of the Fuel Pressure Regulator Valve (N276) and fuse SB14 in Fuse Panel B for an open, short or high resistance.
- Repair as necessary.
If the specified value was obtained:
- Turn the ignition switch ON.
- Connect a multimeter red lead to terminal 1 of the Fuel Pressure Regulator Valve (N276) and the other meter lead to ground.
Specified value: Near 3.40 V.
- Turn the ignition switch OFF.
If the specified value was Not obtained:
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 1 to the Motronic Engine Control Module (ECM) (J623) electrical harness connector T60 terminal for a short to ground or voltage, high resistance or an open circuit.
Specified value: 1.5 ohms max.
If the specification is not obtained:
- Check the wires for a short circuit to each other, a short to battery voltage, and a short to ground.
- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
- Repair as necessary.
If no malfunction is detected in the wiring and the voltage was not correct:
- Replace the Engine Control Module (ECM) (J623). Refer to the service information for procedures.
Final procedures
After 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 ] Readiness Code.