Leak Detection Pump V144, Checking

WARNING: This page is about a different car, the 2006 Audi A4, 2005 Audi A4, 2004 Audi A4, 2003 Audi A4, and 2002 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.

Special tools, testers and auxiliary items required

Multimeter.
Wiring diagram.

Test requirements

Fuse S234 OK.
The Fuel Pump (FP) Relay J17 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
- 66 EXTERIOR EQUIPMENT
- 66 - EXTERIOR EQUIPMENT for BODY EXTERIOR - CABRIOLET
.

Start diagnosis

Remove the right front wheel.
Remove the right front wheel housing liner.

Fig 1: Disconnecting Leak Detection Pump (LDP) V144 Electrical Harness Connector

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Disconnect the Leak Detection Pump (LDP) V144 electrical harness connector - 3 -.

Checking internal resistance

Fig 2: Locating 3-Pin Connector At Fuel System Leak Detection Pump V144

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Using a Multimeter, check the Leak Detection Pump (LDP) V144 for resistance as follows:

Leak Detection Pump (LDP) V144 electrical harness connector terminals	Specified values
- 1 - + - 3 -	640 to 720 Ω
- 2 - + - 3 -	15 to 17 Ω

If any of the specifications are not obtained:

Replace the Leak Detection Pump (LDP) -V144-. Refer to 20 - FUEL SUPPLY SYSTEM .

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.

Fig 3: Identifying 3-Pin Electrical Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

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.

If the specified value was not obtained:

Fig 4: Identifying 3-Pin Electrical Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Using a Multimeter, check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 3 to the Fuel Pump (FP) Relay J17 socket 2 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 wiring

If the manufacturers test box is being used, perform the following step.

Install the test box VAG1598/31. Refer to 24 MULTIPORT FUEL INJECTION (MFI) .

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

Remove the Motronic Engine Control Module (ECM) J220. Refer to → Motronic Engine Control Module (ECM) J220, Replacing .
Using a Multimeter, check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 1 to Motronic Engine Control Module (ECM) J220 electrical harness connector terminal 80 for resistance.

Fig 5: Identifying 3-Pin Electrical Connector & Terminals

Courtesy of VOLKSWAGEN UNITED STATES, INC.

Using a Multimeter, check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 2 to Motronic Engine Control Module (ECM) J220 electrical harness connector terminal 25 for resistance.

Leak Detection Pump (LDP) -V144- electrical harness connector terminals	Motronic Engine Control Module (ECM) J220 electrical connector terminals or test box sockets
1	80
2	25

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:

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 Description .

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) J220. Refer to → Motronic Engine Control Module (ECM) J220, Replacing .
Assembly is performed in the reverse of the removal.

Final procedures

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 Description .

End of diagnosis