Fuel Pressure Regulator Valve, Checking
Special tools and workshop equipment required
- Multimeter.
- Wiring diagram.
Test requirements
- The Fuel Pump (FP) Control Module -J538- OK.
- The 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
Start diagnosis
-- Remove the engine cover.
Checking resistance
-- Disconnect the Fuel Pressure Regulator Valve -N276- electrical harness connector -2- from the Fuel High Pressure Pump -- -1-.
-- Using a multimeter, check the Fuel Pressure Regulator Valve -N276- terminals 1 to 2 for resistance.
Specified value: 25 to 35 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:
Checking voltage
Switch the ignition ON.
-- Using a multimeter, check the Fuel Pressure Regulator Valve -N276- electrical harness connector terminal 1 to Ground for voltage.
Specified value: Battery voltage.
Switch the ignition OFF.
If the specified value was Not obtained:
-- Make sure the Fuel Pump Relay 2 -J49- was turned on from the ECM (ECM ground to relay present) and both power inputs to relay are present during key on. Refer to Wiring Diagrams.
-- Check the wiring from the Fuel Pressure Regulator Valve -N276- electrical connector terminal 1 to the Fuel Pump Relay 2 -J49- terminal 5 for a short circuit to Ground, high resistance or an open circuit.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the wiring connection or replace relay as needed.
-- If a short was found, replace fuse 8 in Fuse Panel B
If the specified value was obtained:
Checking wiring
-- Remove the Engine Control Module (ECM) -J623-. Refer to the Repair Information.
-- Using a multimeter, check the Fuel Pressure Regulator Valve -N276- electrical harness connector terminals to the Engine Control Module (ECM) -J623- electrical harness connector T60 terminals for an open circuit according to the chart below.
| Fuel Pressure Regulator Valve -N276- electrical harness connector terminal | Engine Control Module (ECM) -J623- electrical connector T60 terminal or test box socket |
|---|---|
| 2 | 15 |
Specified value: 1.5 Ω Max.
If the specified value was Not obtained:
-- Check the wiring for an open, high resistance or short to ground.
-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.
-- If necessary, repair the faulty wiring connection.
If no malfunctions are found in the wiring and the voltage was present during key on:
-- Replace the Engine Control Module (ECM) -J623-. Refer to the Repair Information.
-- Install the engine cover. Refer to the Repair Information.
Final procedures
After the 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 .