Leak Detection Pump, Checking

Leak Detection Pump, Checking

Observe all safety precautions: => [ Safety Precautions ] Generic Scan Tool

View clean working conditions: => [ Clean Working Conditions ]

Use only gold-plated terminals when servicing any component with gold-plated electrical harness connector terminals.

For wiring diagrams, component locations, and connector views, Refer to the applicable wiring diagram.

Special tools, testers and auxiliary items required

• multimeter

• Wiring diagram.

Test requirements

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

• 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 left rear wheel housing liner. Refer to appropriate service manual.

- 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 appropriate service manual.

If the specified values are obtained:

Checking voltage supply

• The voltage for the Leak Detection Pump (LDP) (-V144-) is supplied via the Fuse SB7 (on fuse panel B).

- 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.










- Operate the starter briefly.

Specified value: battery voltage.

- Switch the ignition off.

If the specified value was not obtained:

- Using a multimeter, check the Leak Detection Pump (LDP) (-V144-)electrical harness connector terminal 3 to the Motronic Engine Control Module (ECM) Power Supply Relay (J271) terminal 8/87 for an open circuit.





Specified value: Wire resistance max 1.5 ohms.

If the specification is not obtained:

- Check the wiring for 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 detected in the wiring and 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) (J623). Refer to appropriate service manual.

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










Specified value: 1.5 ohms max.

If the specification is not obtained:

- Check the wiring for 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) (J623). Refer to appropriate service manual.

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

- Install the left rear wheel housing liner. Refer to appropriate service manual.

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 ] Readiness Code.