With Manufacturer's Scan Tool

Leak Detection Pump (V144) For Fuel System, Checking

Special tools, equipment, test and inspection devices; required accessories







- VAG1526 A hand-held multimeter
- VAG1527 B voltage tester
- VAG1594 A auxiliary measuring tool set
- VAG 1598/31 adapter cable
- Wiring diagram

Checking power supply

Test conditions







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

Test sequence
- Remove fender liner rear right:







- Disconnect 3-way plug of leak detection pump (V144) -arrow-.







- Connect VAG 1527 B adapter cable between contact 3 (Plus) of plug and ground.
- Start engine an let it run at idle.
The LED should be ON.
- Turn off ignition.

If the LED does not light:
- Use wiring diagram to check cable between contact 3 of 3-terminal plug and relay plate for broken connections.
Line resistance: 1.5 Ohms maximum

If the LED illuminates (power supply OK):
- Remove windshield wiper arms and cowl:







- Connect VAG 1598/31 test box to control module wiring.







- Use wiring diagram to check cables between test box and 3-terminal plug for any broken connections.
- Contact 1 + cavity 80
- Contact 2 + cavity 25
- Line resistance: 1.5 Ohms maximum

- Also check cables for short circuits between each other.
Specification: Infinity Ohms

If no fault could be detected in the cables and there was voltage between contact 3 + ground:
- Replace leak detection pump (V144), item -8-.
- Read-out readiness code:
- If fault memory has been erased or engine control module was separated from positive voltage supply, readiness code must be regenerated:

Checking resistances

Test sequence
- Remove rear right Fender liner:







- Disconnect 3-way plug from leak detection pump (V144) -arrow-.







- Connect VAG 1526 A hand-held multimeter for measuring resistance between contacts 1 and 3 of leak detection pump.
Specification: 640 - 720 Ohms.
- Connect VAG 1526 A hand-held multimeter for measuring resistance between contacts 2 and 3 of leak detection pump.
Specification: 12.5 - 19.5 Ohms.

If the specifications were not attained:
- Replace leak detection pump for fuel system (V144), item -8-.
- Read-out readiness code:
- If fault memory has been erased or engine control module was separated from positive voltage supply, readiness code must be regenerated: