Leak Detection Pump, Checking

Leak Detection Pump, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• Fuse (SB10) OK.

• The ignition switched off.

• Voltage for the Leak Detection Pump (LDP) (V144) is supplied by the Battery (+).

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 - arrow -.





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

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









Specified value: battery voltage.

- Switch the ignition off.

If the specified value was not obtained:

- Check the Leak Detection Pump (LDP) (-V144-) electrical harness connector terminal 3 to the Battery (A) for an open circuit or short to 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:

Checking wiring

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) (J220). Refer to => [ Engine Control Module ] Engine Control Module.

- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical connector to the Motronic Engine Control Module (ECM) (J220) electrical connector T94 for an open circuit.









Specified value: 1.5 ohms max.

If any of the specifications were 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:

- 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 ] Readiness Code.

- 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) (J220). Refer to => [ Engine Control Module ] Engine Control Module.

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

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.