Fuel Metering Valve, Checking

Fuel Metering Valve, Checking

Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.

Test requirements
- The Fuel Pump (FP) Control Module J538 OK.
- The Engine Component Power Supply Relay J757 OK.
- The fuel filter OK.
- The parking brake engaged.
- The battery voltage at least 12.5 V.
- The selector lever of automatic transmission in position "P" or "N".
- 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. General Diagnosis

Start diagnosis







- Remove the front engine cover - arrows -.







- Remove three screws - arrows - and the engine lifting eye to gain access to the Fuel Metering Valve N290 electrical harness connector.







- Disconnect the Fuel Metering Valve N290 electrical harness connector - 2 -.

Checking internal resistance







- Using a Multimeter , check the Fuel Metering Valve N290 terminals for resistance

Specified value: 450 to 1000 Ohms.

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 harness connector terminal 1 to Ground (GND) for voltage.
- Switch the ignition off.

Specified value: battery voltage.

If the specified value was not obtained:
- Check the wiring from the Fuel Metering Valve N290 electrical harness connector terminal 1 to the Engine Component Power Supply Relay J757 terminal 2/87 for a short circuit to Ground (GND), or an open circuit.
- Check the electrical harness connector for damage, corrosion, lose or broken terminals.
- If necessary, repair the wiring connection.

If no malfunctions are found in the wiring:

Checking wiring connections

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 Engine Control Module (ECM) J623.







- Using a multimeter , check the Fuel Metering Valve N290 electrical harness connector terminal 2 to the Engine Control Module (ECM) J623 electrical harness connector T60 terminal 45 for an open circuit.

Fuel Metering Valve N290 Engine Control Module (ECM) J623
electrical harness connector electrical connector T60
terminal terminal or test box socket
2 45

Specified value: 1.5 Ohms Max.

If the specification was not obtained:
- Check the wiring for a short circuit to each other, Battery (+), and Ground (GND).
- Check the electrical harness connector for damage, corrosion, lose or broken terminals.
- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:
- Replace the Engine Control Module (ECM) J623.







- Install the front engine cover - arrows -.

Final procedures
After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory. Diagnostic Mode 03 - Read DTC Memory
2. If necessary, erase the DTC memory. Diagnostic Mode 04 - Erase DTC Memory
3. If the DTC memory was erased, generate readiness code. Monitors, Trips, Drive Cycles and Readiness Codes

- End of diagnosis