Leak Detection Pump, Checking

Diagnostic Procedures

Leak Detection Pump, Checking

Special tools, testers and auxiliary items required

• Multimeter (VAG1526) or multimeter (VAG1715)

• Connector test kit (VAG1594)

• Wiring diagram

Test requirements

• Fuses in E-box (in plenum chamber, left) must be OK:





• Motronic Engine Control Module (ECM) Power Supply Relay (J271) must be OK, check:

• Ground (GND) connections between engine and chassis must be OK.

• Ignition switched off.

Test sequence

- Remove rear right wheelhousing liner.

- Disconnect 3-pin connector of Leak detection pump (LDP) (V144) (- 2 -).





Checking resistances

- 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: 12.0 to 20.0 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:

- Check wires according to wiring diagram.

Checking wiring

- Connect test box to control module wiring harness , connect test box for wiring test.

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

Specified value: infinite ohms

- Check wire between 3-pin connector terminal 3 and Motronic Engine Control Module (ECM) Power Supply Relay (J271) for open circuit according to wiring diagram

Wire resistance: max. 1.5 ohms

- Erase DTC memory of Engine Control Module (ECM) , Diagnostic mode 4: Reset/erase diagnostic data.

- Generate readiness code.

If no malfunctions are found in wires:

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