Fuel Metering Valve 1, Checking

Fuel Metering Valve 1, 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. Refer to --> [ Preliminary Check ] Preliminary Check.

Start diagnosis

- Disconnect the Fuel Metering Valve (N290) electrical harness connector - arrow -.





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 Motronic Engine Control Module (ECM) (J623). Refer to --> [ Engine Control Module, Replacing ] Engine Control Module, Replacing.

- 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 60 for an open circuit.









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:

- Erase the DTC memory. Refer to --> [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to --> [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

- End diagnosis.

If the DTC does return and no malfunction is detected in the wiring and the voltage supply was OK:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to --> [ Engine Control Module, Replacing ] Engine Control Module, Replacing.

- Assembly is performed in the reverse of the removal.

Final procedures

After repair work, the following work steps must be performed in the mentioned sequence:

1. Check the DTC memory. Refer to --> [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Mode 03 - Read DTC Memory.

2. If necessary, erase the DTC memory. Refer to --> [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Mode 04 - Erase DTC Memory.

3. If the DTC memory was erased, generate readiness code. Refer to --> [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.