Leak Detection Pump Checking

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 Engine Control Module (ECM) Power Supply Relay 2 (J670) through fuse SB-9.

Test procedure

• The engine will need to be at room temperature with a minimum 7 hour shutdown before the ECM will initiate an LDP test. It only occurs once in a drive cycle when all conditions are met.

- 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.

- 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 9 in Fuse Panel B for high resistance, an open circuit or a short circuit to Ground. Refer to Wiring Diagrams.

- 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

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

- Using a multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical connector terminals to 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.

If no malfunction is detected in the wiring, the LDP resistance was OK and the voltage supply was OK:

- Replace the 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.