Leak Detection Pump Checking

Diagnostic Procedures

Leak Detection Pump Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

• Fuse (SB44) 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 2 (J670).

Test procedure

- Observe safety precautions. Refer to => [ Safety Precautions ] Safety Precautions

- Observe Clean Working Conditions. Refer to => [ Clean Working Conditions ] Clean Working Conditions

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

Start diagnosis

- Remove the right rear wheel housing liner. Refer to Body Repair Information.

- Disconnect the Leak Detection Pump (LDP) (V144) electrical harness connector - 3 -.





Checking internal resistance

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









If the specified values were not obtained:

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

If the specified values are obtained:

Checking voltage supply

- Start the engine.

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









Specified value: battery voltage.

- Switch the engine off.

If the specified value was not obtained:

- Check the wiring from the Leak Detection Pump (LDP) (-V144-) electrical harness connector terminal 3 to fuse 44 in Fuse Panel B for high resistance, 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 the specified value was obtained:

Checking output 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 the Repair Information.

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









Specified value: 1.5 ohms.

If the specified value is not obtained:

- Check the wiring for high resistance, an open or a short to voltage or ground.

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

- If necessary, repair the wiring connection.

- 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:

Generate readiness code. Refer to => [ Readiness Code ] Monitors, Trips, Drive Cycles and Readiness Codes.

If the DTC does return, no malfunction is detected in the wiring and the voltage supply is OK:

- Replace the Motronic Engine Control Module (ECM) (J623). Refer to the Repair Information.

- Assembly is performed in the reverse of the removal.

Final procedures

After repair work, the following work steps must be performed in the mentioned 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 ] Monitors, Trips, Drive Cycles and Readiness Codes.