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 Metering Valve -N290- electrical harness connector from the Fuel High Pressure Pump --.

-- Using a multimeter, check the Fuel Metering Valve -N290- 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 Metering Valve -N290-.

If the specified value was obtained:

Checking voltage

Switch the ignition On.

-- Using a multimeter, check the Fuel Metering Valve -N290- electrical connector terminal 1 to Ground for voltage.

Specified value: Battery voltage.

Switch the ignition Off.

If the specified value was Not obtained:

Checking wiring

-- Remove the Engine Control Module (ECM) -J623-.

-- Using a multimeter, check the Fuel Metering Valve -N290- electrical harness connector terminals to the Engine Control Module (ECM) -J623- electrical harness connector T105 terminals for an open circuit. Refer to Wiring Diagrams.

Fuel Metering Valve -N290- electrical harness connector terminal:	Engine Control Module (ECM) -J623- electrical connector T105 terminal:
2	92

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:

-- Replace the Engine Control Module (ECM) -J623-.

-- Install the engine cover with air filter.

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 .