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Leak Detection Pump, Checking

Special tools and workshop equipment required 

Test requirements 

Test procedure 

-- Perform a preliminary check to verify the customers complaint. Refer to PRELIMINARY CHECK 

Start diagnosis 

-- Remove the right rear wheel housing liner. Refer to the Repair Information.

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

Fig 1: Disconnecting Leak Detection Pump (LDP) V144 Electrical Harness Connector
GWWA20-10094Courtesy of VOLKSWAGEN UNITED STATES, INC.

Checking internal resistance 

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

Fig 2: Checking Leak Detection Pump (LDP) V144 For Resistance
GWWA24-0123Courtesy of VOLKSWAGEN UNITED STATES, INC.
Leak Detection Pump (LDP) -V144- electrical connector terminals: Specified values:
-1- to -3- 640 to 720 Ω
-2- to -3- 15 to 17 Ω

If the specified values were Not obtained: 

-- Replace the Leak Detection Pump (LDP) --V144--. Refer to the Repair Information.

If the specified values were obtained: 

Checking voltage supply 

NOTE:

The voltage for the Leak Detection Pump (LDP) --V144-- is supplied via fuse 15 in fuse panel B.

-- 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. Connect the negative multimeter lead to engine ground.

Fig 3: 3-Pin Electrical Harness Connector & Terminals
GWWN24-1648Courtesy of VOLKSWAGEN UNITED STATES, INC.

-- Turn the ignition switch ON.

Specified value: Battery voltage.

-- Switch the ignition OFF.

If the specified value was Not obtained: 

-- Remove fuse 16 in Fuse Panel B. Using a multimeter, check the Leak Detection Pump (LDP) --V144-- wiring from terminal 3 to fuse 16.

Specified value: 1.5 Ω max.

If the specified value was Not obtained: 

-- Check the wiring for high resistance, short to ground or an open circuit.

-- Check the electrical harness connector for damage, corrosion, loose or broken terminals.

-- If necessary, repair the faulty wiring connection.

If the specified value was obtained: 

Checking wiring 

-- Remove the Engine Control Module (ECM) -J623-. Refer to the Repair Information.

-- Using a multimeter, check the Leak Detection Pump (LDP) --V144-- electrical connector terminals to Engine Control Module (ECM) -J623- electrical connector terminals for an open circuit or high resistance.

Leak Detection Pump (LDP) --V144-- electrical harness connector terminal: Engine Control Module (ECM) -J623- electrical connector T94 terminal:
1 44
2 49

Specified value: 1.5 Ω max.

If the specified value was Not obtained: 

-- Check the wiring for high resistance 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 the Repair Information.

Assembly is performed in the reverse order of the removal, note the following:

-- Install the right rear wheel housing liner. Refer to the Repair Information.

Final procedures 

After the repair work, the following work steps must be performed in the following sequence:

  1. Check the DTC memory. Refer to DIAGNOSTIC MODE 03 - READ DTC MEMORY .
  2. If necessary, erase the DTC memory. Refer to DIAGNOSTIC MODE 04 - ERASE DTC MEMORY .
  3. If the DTC memory was erased, generate readiness code. Refer to READINESS CODE .