Leak Detection Pump (LDP) V144, Checking

Leak Detection Pump (LDP) V144, checking

Special tools, testers and auxiliary items required
- Multimeter
- Wiring diagram

Test requirements
- The Leak Detection Pump (LDP) V144 fuse OK.
- The Fuel Pump (FP) Relay J17 OK.
- The ignition switched off.

Test procedure
- Perform a preliminary check to verify the customers complaint.

Start diagnosis
- Remove the right rear wheel housing liner.






- Disconnect the Leak Detection Pump (LDP) V144 electrical harness connector -arrow-.

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-.

If the specified values are obtained:

Checking voltage supply

Note:
The voltage for the Leak Detection Pump (LDP) -V144- is supplied by the Fuel Pump (FP) Relay J17.

- 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 Fuel Pump (FP) Relay J17 terminal 23/87 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, lose 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 Test Box 105 Pin VAG1598/31.

If the manufacturers test box is not being used. Perform the following step.

- Remove the Motronic Engine Control Module (ECM) J220. Service and Repair

- Using a Multimeter, check the Leak Detection Pump (LDP) -V144- electrical connector terminal 1 to Motronic Engine Control Module (ECM) J220 electrical connector T121 terminal 40 for an open circuit.






- Using a Multimeter, check the Leak Detection Pump (LDP) -V144- electrical connector terminals to the Motronic Engine Control Module (ECM) J220 electrical connector T121 terminals for an open circuit.






Specified value: 1.5 Ohms max.

If the specification is not obtained:
- Erase the DTC memory. Diagnostic Mode 4: Reset/Erase Diagnostic Data
- Perform a road test to verify repair.

If the DTC does not return:
Repair complete, Generate 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 MFI Engine Control Module (ECM) J220. Service and Repair
- Assembly is performed in the reverse of the removal.
- Assembly is performed in the reverse order of the removal, note the following:
- Install the right rear wheel housing liner.

Final procedures

After the repair work, the following work steps must be performed in the following sequence:
1. Check the DTC memory.
2. If necessary, erase the DTC memory.
3. If the DTC memory was erased, generate readiness code.

End diagnosis