Leak Detection Pump, Checking

Leak Detection Pump, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Leak Detection Pump (LDP) (V144) Engine Electronics Fuse (S282) OK.

• The ignition switched off.

• The voltage for the Leak Detection Pump (LDP) (-V144- ) is supplied via the Fuel Pump (FP) Relay (J17 ).

Procedure

- Remove the left rear wheel housing liner.

- Disconnect the Leak Detection Pump (LDP) (V144 ) electrical harness connector.





Checking internal resistance

- Using a Multimeter, check the Leak Detection Pump (LDP) (V144) for resistance as follows:









If any of the specifications were not obtained:

- Replace the Leak Detection Pump (LDP) (-V144- ). Refer to Fuel Supply Repair Information.

If the specified values were obtained:

Checking voltage supply

- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical harness connector terminal 3 to Ground (GND) for voltage.









- Operate the starter briefly.

Specified value: battery voltage.

- Switch the ignition off.

If the specified value was not obtained:

- Check the wiring 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 faulty wiring connection.

It the specification was obtained.

Checking wiring

If the manufacturers test box is being used. Perform the following step.

- Install the test box. Refer to Fuel Injection and Ignition Repair Information.

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 ] Service and Repair.

- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical harness connector terminals to the Motronic Engine Control Module (ECM) (J623 ) electrical harness connector T121 terminals for an open circuit.









Specified value: 1.5 ohms.

If the specification is not obtained:

- Check the wiring for a short circuit to Battery positive (+) or an open circuit.

- Check the electrical harness connector for damage, corrosion, lose or broken terminals.

- If necessary, repair the wiring connection.

If no malfunction is found in wiring:

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

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

- Install the right rear wheel housing liner.

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 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.