Leak Detection Pump, Checking

Diagnostic Procedures

Leak Detection Pump, Checking

Special tools, testers and auxiliary items required

• (VAG1526A)

• (VAG1527B)

• (VAG1594A)

• (VAG1598/31)

- Remove Leak detection pump (LDP) (V144), refer to Repair Manual and disconnect electrical harness connector.

Resistance, Checking

- Connect multimeter for resistance measurement as follows.









If specified values are not obtained:

- Replace Leak detection pump (LDP) (V144), refer to Repair Manual.

If specified values are obtained:

- Check voltage supply of Leak Detection Pump (LDP).

Voltage Supply, Checking

• Voltage is supplied to the Leak Detection Pump (LDP) via the Fuel Pump (FP) relay.

Test Prerequisite

• Fuse for Leak Detection Pump (LDP) OK.

- Connect multimeter for voltage measurement as follows:









- Operate starter briefly.

Specified value: approx. battery voltage

- Switch ignition off.

If specified value is not obtained

- Check electrical wire connection from terminal 3 to Fuel Pump (FP) relay via fuse for open circuit according to wiring diagram.





- Repair open circuit in wiring if necessary.

- If voltage supply is OK, check wire connection.

Engine Control Module, Checking Ground

- Connect multimeter as follows:









- Operate starter briefly.

Specified value: approx. battery voltage

- Switch ignition off.

If the specified values are not reached, check wire connection.

Wire Connections, Checking

- Connect test box (VAG1598/31) to harness connectors of wiring harness (do not connect ECM). Connect Ground (GND) clip at test box (not visible in illustration) to Ground (GND), refer to Repair Manual.





- Check the following wire connection for open circuit and short circuit to Ground (GND) and B+:









- Repair open circuit in wiring or short circuit if necessary.

- In addition, check both wires to each other for short circuit.

Specified value: infinite ohms (no continuity)

- If no malfunction was detected during the previous tests, replace Engine Control Module (ECM), refer to Repair Manual.

- Read readiness code => [ Readiness Code, Reading ] Monitors, Trips, Drive Cycles and Readiness Codes. If DTC memory was erased, readiness code must be generated again => [ Readiness Code, Generating ] Monitors, Trips, Drive Cycles and Readiness Codes.