Leak Detection Pump, Checking
Leak Detection Pump, Checking
Special tools, testers and auxiliary items required
• Multimeter.
• Wiring diagram.
Test requirements
• The Fuel Pump (FP) (G6) OK.
• Leak Detection Pump (LDP) (V144) fuse OK.
• The ignition switched off.
Test procedure
- Perform a preliminary check to verify the customer's complaint. Refer to => [ Preliminary Check ] Preliminary Check.
- Remove the left rear wheel housing liner.
- Disconnect the electrical harness connector - 3 -.
Checking internal resistance
- Using a Multimeter , check the Leak Detection Pump (LDP) (V144) for resistance as follows:
If the specifications are not obtained:
- Replace the Leak Detection Pump (LDP) (-V144-).
If the specified values are obtained:
Checking voltage supply
• The voltage for the Leak Detection Pump (LDP) (-V144-) is supplied through the the Engine Control Module (ECM) (J623).
- 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.
- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical harness connector terminal 3 to the Engine Control Module (ECM) (J623) connector T60, socket 45, through the the Fuel Metering Valve (N290), for resistance.
Specified value: 1.5 ohms max
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 was OK:
Checking output wiring
If the manufacturers test box is being used, perform the following step.
- Connect the test box (VAG1598/42) to the wiring harness of the Engine Control Module (ECM) (J623) with adapter cable (VAG1598/39-1).
If the manufacturers test box is not being used, perform the following step.
Remove the 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 1 to Engine Control Module (ECM) (J623) electrical harness connector terminal 20 for resistance.
- Using a Multimeter, check the Leak Detection Pump (LDP) (-V144-) electrical harness connector terminal 2 to Engine Control Module (ECM) (J623) electrical harness connector terminal 24 for resistance.
Specified value: 1.5 ohms max.
If the specification is not obtained:
- Check the wiring for a short circuit to Battery positive (+), Ground (GND) 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 Engine Control Module (ECM) (J623). Refer to=> [ Engine Control Module, Replacing ] Engine Control Module, Replacing
If the specification was obtained:
- 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 and switch ignition off.
- Assembly is performed in the reverse of the removal.
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 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.