Volkswagen Workshop Service and Repair Manuals

Special tools, workshop equipment, testers, measuring instruments and auxiliary items required

• ◆ Test box V.A.G 1598/22
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Test conditions

• ● → Fuse 43 must be OK.
• ● The battery voltage must be at least 11.5 V.
• ● Fuel pump relay must be OK

Test sequence

• ‒ → Remove protective cover -arrows- and separate 4 pin connector (black) to Lambda probe before catalyst (G39).

• ‒ → Check probe heating at connector contacts 1+2 for continuity

Note:

The heater element resistance is approx. 1...5 ω at room temperature. Even slight increases in room temperature increase the resistance greatly.

If it is determined that probe heating has an open circuit:

• ‒ Replace Lambda probe (G39).

If probe heating has continuity:

• ‒ → Set multimeter to measure voltage and connect to contacts 1 and 2 on connector to control unit.
• ‒ Start engine and run at idling speed.

•      Specification: 11...15 V

• ‒ Switch off ignition.

If no voltage is present:

• ‒ → Connect test box V.A.G 1598/22 to control unit wiring harness.

• ‒ → Check wiring between test box and 4 pin connector for open circuit according to current flow diagram.
       Contact 2+socket 27
       Wire resistance: Max. 1.5 ω

If the specification is obtained:

• ‒ Check wiring from contact 1 to fuel pump relay (J17) according to current flow diagram.

=> Current flow diagrams, Electrical fault finding and Fitting locations binder