Fuel Metering Valve 2, Checking

Fuel Metering Valve 2, Checking

The following procedure is used to diagnose the Fuel Metering Valve 2 (N402) which is controlled by Motronic Engine Control Module (ECM) (J623).

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Engine Component Power Supply Relay (J757) OK.

• The Fuse (S 13) 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.

• 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 2 (N402) electrical harness connector - arrow -.in l.h. high pressure pump.





Checking internal resistance

- Using a Multimeter , check the Fuel Metering Valve 2 (N402) terminals 1 to 2 for resistance





Specified value: 450 to 1000 ohms.

If the specified value was not obtained:

- Replace the Fuel Metering Valve 2 (N402). Refer to appropriate service manual.

If the specified value was obtained:

Checking voltage

Crank the engine.

- Using a Multimeter, check the Fuel Metering Valve 2 (N402) 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 2 (N402) electrical harness connector terminal 1 to the Fuse (on fuse/relay panel) (S 13) for an open circuit or a short circuit to Ground (GND).

- Check the electrical harness connector for damage, corrosion, loose 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). Refer to appropriate service manual.

- Using a multimeter, check the Fuel Metering Valve 2 (N402) electrical harness connector terminal 2 to the Engine Control Module (ECM) (J623) electrical harness connector T60 terminal 35 for resistance.










Specified value: 1.5 ohms Max.

If the specification was not obtained:

- Check the wiring for an open circuit, a short circuit to each other, Battery (+) or Ground (GND).

- 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 Modes 01 - 09.

- Perform a road test to verify repair.

If the DTC does not return:

Repair complete, Generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.

If the DTC returns and no malfunction is found in the wiring and voltage supply was OK:

- Replace the Engine Control Module (ECM) (J623). Refer to appropriate service manual.

Assembly is performed in the reverse order of the removal, note the following:

Final procedures

After 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 - 09.

2. If necessary, erase the DTC memory. Refer to => [ Diagnostic Mode 04 - Erase DTC Memory ] Diagnostic Modes 01 - 09.

3. If the DTC memory was erased, generate readiness code. Refer to => [ Readiness Code ] Programming and Relearning.