Leak Detection Pump (LDP) V144 , Checking

Leak Detection Pump (LDP) V144, Checking

Special tools, testers and auxiliary items required
- Multimeter V.A.G 1526 or equivalent.
- Test Box 105 Pin VAG1598/42.
- Adapter Lead Vag1598/39 VAG1598/39.
- Adapter Lead Vag1598/39 VAG1598/39.

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

Procedure
- Remove the left rear wheel housing liner.







- Disconnect the electrical harness connector - 3 - .

Checking internal resistance







- Using the Multimeter V.A.G. 1526 A or equivalent, check them Leak Detection Pump (LDP) V144 for resistance as follows:

Leak Detection Pump (LDP) -V144- terminal Specified value
- 1 - + - 3 - 640 to 720 Ohms
- 2 - + - 3 - 15 to 17 Ohms

If the specifications are not obtained:
- Replace the Leak Detection Pump (LDP) -V144- .

If the specified values are obtained:
- Check the voltage supply of the Leak Detection Pump (LDP) -V144- .

Checking voltage supply

NOTE: The voltage for the Leak Detection Pump (LDP) -V144- is supplied via the Engine Control Module (ECM) J623.







- Using the Multimeter V.A.G. 1526 A or equivalent, check the electrical harness connector for voltage.

Harness connector terminal Measure to
- 3 - Engine Ground (GND)

- Operate the starter briefly.
Specified value: aprox. battery voltage.
- Switch the ignition off.

If the specified value was not obtained:







- Using the Multimeter V.A.G. 1526 A or equivalent, check electrical harness connector terminal - 3 - via Fuel Metering Valve N290 to Engine Control Module (ECM) J623 for 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.
- 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
- Connect the test box 1598/42 to the wiring harness of the Engine Control Module (ECM) J623. The ECM is not connected.







- Using the Multimeter V.A.G. 1526 A or equivalent, check the following wire connections for an open circuit.

Harness connector terminal Test box Socket
- 1 - 40
- 2 - 8

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.
- If necessary, repair the wiring connection.

If no malfunction is found in wiring:
- Replace the Engine Control Module (ECM) J623.

Assembly is performed in the reverse order of the removal, note the following:
- Install the left rear wheel housing liner.

Final procedures
After repair work, the following work steps must be performed in the mentioned 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 and switch ignition off.