Leak Detection Pump, Checking

Leak Detection Pump, Checking

Special tools, testers and auxiliary items required

• multimeter

• Wiring diagram.

Test requirements

• The Fuse (SA15) fuse OK.

• The ignition switched off.

• The voltage for the Leak Detection Pump (LDP) (-V144-) is supplied by the Motronic Engine Control Module (ECM) Power Supply Relay (J271).

Test procedure

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

Start diagnosis

- Remove right rear wheel housing liner.

- Disconnect the Leak Detection Pump (LDP) (V144) electrical harness connector - 4 -.





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-).

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 connection from the Leak Detection Pump (LDP) (-V144-) electrical harness connector terminal 3 to the Motronic Engine Control Module (ECM) Power Supply Relay (J271) terminal 2/87 for an open circuit or short to ground (GND).

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

- If necessary, repair the wiring connection.

If the specified value was obtained:

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) (J623). Refer to => [ Engine Control Module, Removing and Installing ] Engine Control Module, Removing and Installing.

- 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 terminals for resistance.









Specified value: 1.5 ohms.

If the specification was not obtained:

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

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

- If necessary, repair the wiring connection.

If the specification was obtained:

- 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 ] Monitors, Trips, Drive Cycles and Readiness Codes.

- End diagnosis.

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 => [ Engine Control Module, Replacing ] Engine Control Module, Replacing.

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 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.