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 ignition switched off.

Procedure 

• Remove the left rear wheel housing liner. →
  • 66 EXTERIOR EQUIPMENT
  • 66 - EXTERIOR EQUIPMENT for BODY EXTERIOR - CABRIOLET
  .

Fig 1: Identifying Vacuum Line, Electrical Connector, Vent Line & Nuts

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Disconnect the Leak Detection Pump (LDP) V144 electrical harness connector - 2  -.

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:

If any of the specifications are not obtained:

• Replace the Leak Detection Pump (LDP) -V144-. → 20 - FUEL SUPPLY SYSTEM .

If the specified values are obtained:

Checking voltage supply 

Fig 3: Identifying 3-Pin Electrical Connector & Terminals

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• Using a Multimeter , check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 3 to Ground (GND) for voltage.

• 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

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• Using a Multimeter , check the Leak Detection Pump (LDP) -V144- electrical harness connector terminal 3 to the Engine Component Power Supply Relay J757 terminal 2/87 for resistance.

Specified value: 1.5 Ohms

If the specified value was not obtained:

• Check the wiring for a short circuit to Ground (GND) 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. 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 (ECM) J623 , Removing and Installing .
• Using a Multimeter , check the Leak Detection Pump (LDP) -V144- electrical connector terminal 1 to Engine Control Module (ECM) J623 electrical connector T94 terminal 20 for an open circuit.

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 connector terminal 2 to Engine Control Module (ECM) J623 electrical connector T94 terminal 24 for an open circuit.

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, lose 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 (ECM) J623 , Removing and Installing .

Fig 6: Removing/Installing Rear Engine Cover

Courtesy of VOLKSWAGEN UNITED STATES, INC.

• Install the rear engine cover - arrows  -.

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. Refer to Diagnostic Mode 04: Reset/delete Diagnostic Data .
3. If the DTC memory was erased, generate readiness code. Refer to Readiness Code .

• End of diagnosis.