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 customers complaint. Refer to → Preliminary Check .
- Remove the left rear wheel housing liner. Refer to the appropriate service information
- Disconnect the electrical harness connector - 3 -.
Checking internal resistance
- Using a Multimeter , check the Leak Detection Pump (LDP) V144 for resistance as follows:
| Leak Detection Pump (LDP) -V144- terminal | Specified value |
|---|---|
| 1 to 3 | 640 to 720 Ω |
| 2 to 3 | 15 to 17 Ω |
If the specifications are not obtained:
- Replace the Leak Detection Pump (LDP) -V144-. → Refer to the appropriate service information
If the specified values are obtained:
Checking voltage supply
- The voltage for the Leak Detection Pump (LDP) -V144- is supplied through the Engine Control Module (ECM) J623.
- Using a Multimeter , check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 3 for voltage.
| Leak Detection Pump (LDP) -V144- electrical harness connector terminal | Measure to |
|---|---|
| 3 | Engine Ground (GND) |
- 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 Fuel Metering Valve N290 , for resistance.
Specified value: 1.5 Ω 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. Refer to 24 - FUEL INJECTION SYSTEM .
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
- 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.
| Leak Detection Pump (LDP) -V144- electrical harness connector terminals | Engine Control Module (ECM) J623 electrical connector terminals or test box sockets |
|---|---|
| 1 | 20 |
| 2 | 24 |
Specified value: 1.5 Ω 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
If the specification was obtained:
- Erase the DTC memory. Refer to → Diagnostic Mode 04 - Reset/Delete Diagnostic Data .
- Perform a road test to verify repair.
If the DTC does not return:
Repair complete, Generate readiness code. Refer to → Readiness Code .
- 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:
- Check the DTC memory.
- If necessary, erase the DTC memory. Refer to Diagnostic Mode 04 - Reset/Delete Diagnostic Data .
- If the DTC memory was erased, generate readiness code. Refer to Readiness Code .