Leak Detection Pump (Ldp), Checking

Leak Detection Pump (LDP), checking

Recommended special tools and equipment
- VAG 1526 multimeter or VAG 1715 multimeter
- VAG 1594 connector test kit
- Wiring diagram

Test requirements






- The respective fuses of Leak detection pump (LDP) -V144- must be OK:
- Ignition switched off.

Test sequence

- Remove wheelhouse liner, rear left.






- Disconnect 3-pin connector of Leak detection pump (LDP) -V144- (arrow).






- Measure resistance between terminals 1 & 3 of diagnostic pump.

Specified value: 640 to 720 Ohms

- Measure resistance between terminals 2 & 3 of diagnostic pump.

Specified value: 17.5 to 19.5 Ohms

If specified values are not obtained:

- Replace Leak Detection Pump (LDP) -V144-.

- Erase DTC memory of Engine Control Module (ECM). Diagnostic Mode 4: Reset/Erase Diagnostic Data

- Generate readiness code.

If specified values are obtained:

- Connect test box to control module wiring harness.






- 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 circuits to each other, to vehicle Ground (GND) and to B+.

Specified value: Infinity Ohms

- Check wire between 3-pin connector terminal 3 and the Fuel Pump (FP) Relay -J17- for open circuit according to wiring diagram.

Wire resistance: max: 1.5 Ohms

If no malfunctions are found in wires:

- Replace Motronic Engine Control Module (ECM) -J220-.