Fuel Pressure Regulator Valve Checking
Observe all safety precautions: SAFETY PRECAUTIONS
View clean working conditions: CLEAN WORKING CONDITIONS
Prior to repair work, perform a preliminary check to verify the condition. Refer to 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 and workshop equipment 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 Ω (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.
| Fuel Pressure Regulator Valve -N276- electrical harness connector terminal | Engine Control Module (ECM) -J623- electrical harness connector T60 terminals or test box socket |
|---|---|
| 1 | 45 |
Specified value: 1.5 Ω 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 removal and installation procedures.
Final procedures
After repair work, the following work steps must be performed in the following sequence:
- Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
- If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
- If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .