Leak Detection Pump: Testing and Inspection

Leak Detection Pump (LDP), Checking

Special tools, workshop equipment, test and measuring appliances and aux. items required







- V.A.G 1526 A Hand multimeter
- VAG 1527 B voltage tester
- V.A.G 1594 A Adapter set
- V.A.G 1598/31 Test box
- Wiring diagram

Electrically checking diagnosis pump
- Remove rear right wheel housing liner:







- Pull the 3 pin connector off the diagnosis pump (V144).
- Connect hand multimeter V.A.G 1526 A to measure resistance between the contacts 1 and 3 of -V144. Specification: 640 . . .720 Ohms.
- Connect hand multimeter V.A.G 1526 to measure resistance between the contacts 2 and 3 of -V144. Specification: 12.5 .. .19.5 Ohms.

If the specifications are not attained:
- Replace the diagnosis pump -V144
- Check DTC memory:
- Read out readiness code:
- If the DTC memory has been erased or the engine control module separated from the permanent positive, the readiness code must be generated again.

Checking voltage supply

Test conditions







- Fuse No. 43 must be OK.
- The battery voltage must be at least 11.5 V.

Test sequence
- Remove rear right wheel housing liner:







- Pull the 3 pin connector off the diagnosis pump (V144).
- Connect the VAG 1527 B voltage tester between connector contact 3 (positive) and engine Ground.
- Start engine and run at idling speed: The LED must light up.

If the LED does not light up:
- Switch off ignition.
- Check the wire between connector contact 3 and central electrics for open circuit using wiring diagram: Wire resistance: max. 1.5 Ohms

LED lights up (voltage supply OK.):







- Connect test box V.A.G 1598/31 to control module wiring harness. The engine control module remains disconnected.







- Check wiring between test box and 3 pin connector for open circuit using wiring diagram. Contact 1 + socket 80 Contact 2 + socket 25 Wire resistance: max. 1.5 Ohms
- Additionally check wires for short to one another. Specification: Infinity Ohms

If no wiring fault is detected and voltage was present between contacts 3 and Ground:
- Replace the diagnosis pump -V144
- Check DTC memory:
- Read out readiness code:
- If the DTC memory has been erased or the engine control module separated from the permanent positive, the readiness code must be generated again.