Leak Detection Pump, Checking

Diagnostic Procedures

Leak Detection Pump, Checking

Special tools, testers and auxiliary items required

• Multimeter.

• Wiring diagram.

Test requirements

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

• The engine must be completely cooled down. IAT must match ECT within 5 Degrees C in order for the LDP to operate. Let sit overnight if possible when testing for voltage to the pump motor.

• 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. Refer to the Repair Information.

- 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- ). Refer to the Repair Information.

If the specified value was obtained:

Checking voltage supply

- 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. Connect the negative multimeter lead to engine ground.





- Start the engine.

Specified value: Battery voltage.

- Switch the ignition OFF.

If the specified value was Not obtained:

- Remove fuse S-243. Using a multimeter, check the Leak Detection Pump (LDP) (-V144-)wiring from terminal 3 to fuse S-243.

Specified value: 1.5 ohms max

If the specified value was Not obtained:

- Check the wiring for high resistance or an open circuit.

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

- If necessary, repair the faulty wiring connection.

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

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 the Repair Information.

- Using a multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical connector terminal 1 to Motronic Engine Control Module (ECM) (J220) electrical connector T121 terminal 80 for an open circuit or high resistance.

- Using a multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical connector terminal 2 to Motronic Engine Control Module (ECM) (J220) electrical connector T121 terminal 25 for an open circuit or high resistance.





Specified value: 1.5 ohms max.

If the specified value was Not obtained:

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

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

- If necessary, repair the faulty wiring connection.

If no malfunction is found in wiring:

- Replace the Motronic Engine Control Module (ECM) (J220). Refer to the Repair Information.

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

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

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 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.