Leak Detection Pump: Testing and Inspection

Leak Detection Pump (LDP), Checking

Special tools and equipment
- Multimeter (Fluke 83 or equivalent)
- VAG1527B voltage tester
- VAG1594A connector test kit
- VAG 1598/31 test box
- Wiring diagram

Electrically checking Leak Detection Pump (LDP)

- Remove 3-pin connector -1- for Leak Detection Pump (LDP) -V144-.
- Connect Multimeter (Fluke 83 or equivalent) between terminals 1 and 3 of Leak Detection Pump (LDP) for resistance measurement.
Specification: 640 to 720 Ohms.
- Connect Multimeter (Fluke 83 or equivalent) between terminals 2 and 3 of Leak Detection Pump (LDP) for resistance measurement.
Specification: 14 to 18 Ohms.

If specified values are not obtained:
- Replace Leak Detection Pump (LDP) -V144-

Checking voltage supply

Test requirement

- All fuses must be OK.

Test sequence

- Remove 3-pin connector -1- for Leak Detection Pump (LDP) -V144-.
- Connect VAG1527B voltage tester between terminal 3 (B + ) of connector and engine Ground (GND).
- Start engine, and let run at idle LED must light up.

If LED does not light up:
- Check for open circuits in wire between connector terminal 3 and central electronics according to wiring diagram:
- Switch ignition off.

Checking wiring

- Connect VAG 1598/31 test box to control module wiring harness. Engine Control Module (ECM) is not connected.

- Check wires between test box and 3-pin connector for open circuits according to wiring diagram.
Terminal 1 + socket 80
Terminal 2 + socket 25
Wire resistance: max: 1.5 Ohms

- Also check wires for short circuit to each other.
Terminal 3 + socket 25
Terminal 3 + socket 80
Terminal 2 + socket 80
Specification: Infinity Ohms

If no malfunctions are found in wires:
- Replace Leak Detection Pump (LDP) -V144-
- Perform work procedure "Procedure to follow after interruption of voltage supply":
- Read readiness code:
- If DTC memory was erased or the Engine Control Module (ECM) was disconnected from the continuous B+ supply, the readiness code must be re-generated: