Leak Detection Pump V144, Checking

Leak Detection Pump V144, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• The Leak Detection Pump (LDP) (V144) fuse OK.

• The ignition switched off.

Test procedure

- Perform a preliminary check to verify the customers complaint. Refer to => [ Preliminary Check ] Preliminary Check

Start diagnosis

- Remove the right rear wheel housing liner.

- Disconnect the Leak Detection Pump (LDP) (V144) electrical harness connector - 2 -.





Checking internal resistance

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










If any of the specifications are not obtained:

- Replace the Leak Detection Pump (LDP) (-V144-).

If the specified values are obtained:

Checking voltage supply

• The voltage for the Leak Detection Pump (LDP) (-V144-) is supplied by the Engine Control Module (ECM) (J623).

- Check the Leak Detection Pump (LDP) (-V144-) for voltage.

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










- Operate the starter briefly.

Specified value: battery voltage.

- Switch the ignition off.

If the specified value was not obtained:

- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-)electrical harness connector terminal 3 to the Engine Component Power Supply Relay (J757) terminal 2/87 for an open circuit.





Specified value: Wire resistance max 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 faulty wiring connection.

If no malfunction is detected in the wiring and if the voltage supply was OK:

Checking wiring

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

- Install the Test Box 105 Pin (VAG1598/42).

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 J623, Removing and Installing ] Engine Control Module J623, Removing and Installing.

- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical connector terminal 1 to Motronic Engine Control Module (ECM) (J623) electrical connector T94 terminal 40 for an open circuit.

- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical connector terminals to the Motronic Engine Control Module (ECM) (J623) electrical connector T94 terminals for an open circuit.










Specified value: 1.5 ohms max.

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 faulty wiring connection.

If no malfunction is found in wiring:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to => [ Engine Control Module J623, Removing and Installing ] Engine Control Module J623, Removing and Installing.

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

- Install the right rear wheel housing liner.

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 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 ] Readiness Code Description.

End of diagnosis