Fuel Metering Valve, Checking

Fuel Metering Valve, Checking

Fuel Metering Valve

The Fuel Metering Valve (N290) is controlled by the Engine Control Module (ECM) (J623).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Fuel Pump (FP) Control Module (J538) OK.

• The Motronic Engine Control Module (ECM) Power Supply Relay (J271) OK.

• The Fuse (SC5) 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

- Disconnect the Fuel Metering Valve (N290) electrical harness connector - 1 -.





Checking internal resistance

- Using a Multimeter , check the Fuel Metering Valve (N290) terminals 1 to 2 for resistance





Specified value: 450 to 1000 ohms.

If the specified value was not obtained:

- Replace the High Pressure Fuel Pump. Refer to appropriate repair information.

If the specified value was obtained:

Checking voltage

Crank the engine.

- Using a Multimeter, check the Fuel Metering Valve (N290) electrical harness connector terminal 1 to Ground (GND) for voltage.





Specified value: battery voltage.

- Switch the ignition off.

If the specified value was not obtained:

- Check the wiring from the Fuel Metering Valve (N290) electrical harness connector terminal 1 to the Motronic Engine Control Module (ECM) Power Supply Relay (J271) socket 2/30 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. Refer to appropriate repair information.

If the manufacturers test box is not being used, perform the following step.

- Remove the Engine Control Module (ECM) (J623). Refer to appropriate repair information

- 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 19 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), or an open circuit.

- If necessary, repair the faulty wiring connection.

If no malfunction is detected in the wiring:

- Replace the Engine Control Module (ECM) (J623). Refer to appropriate repair information.

- Assembly is performed in the reverse order of removal.

Final procedures

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

1. Check the DTC memory. Refer to => [ Diagnostic Mode 03 - Read DTC Memory ] Diagnostic Modes 01 - 0A.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 0A.

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