Leak Detection Pump, Checking
Leak Detection Pump, Checking
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• The Leak Detection Pump (LDP) (V144) fuse OK.
• The ignition switched off.
• The voltage for the Leak Detection Pump (LDP) (-V144-) is supplied via 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 the left 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 specifications was not obtained:
- Replace the Leak Detection Pump (LDP) (-V144-).
If the specified values are 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 to Ground (GND) for voltage.
- Operate the starter briefly.
Specified value: battery voltage.
- Switch the ignition off.
If the specified value was not obtained:
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, Replacing ] Engine Control Module, Replacing.
- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-)electrical harness connector terminal 3 to theMotronic Engine Control Module (ECM) Power Supply Relay (J271) terminal 2/87 for resistance.
Specified value: Wire resistance 1.5 ohms.
If the specification was 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 is OK:
Checking output wiring
- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical connector terminal 1 to Motronic Engine Control Module (ECM) (J623) electrical connector T94 terminal 40 for an open circuit.
- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical connector terminal 2 to Motronic Engine Control Module (ECM) (J623) electrical connector T94 terminal 10 for an open circuit.
Specified value: 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 wiring connection.
- 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 does return and no malfunction is detected in the wiring and the voltage supply was OK:
- Replace the Motronic Engine Control Module (ECM) (J623). Refer to --> [ Engine Control Module, Replacing ] Engine Control Module, Replacing.
- 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 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.