Volkswagen Workshop Service and Repair Manuals

Special tools, testers and auxiliary items

• ◆ Test box V.A.G 1598/18
• ◆ Hand multimeter V.A.G 1526 or multimeter V.A.G 1715
• ◆ Adapter set V.A.G 1594
• ◆ Current flow diagram

Test conditions

• ● Lambda probe heating relay OK.

• ● Coolant temperature at least 80 °C

Test sequence

• ‒ → Separate 4 pin connector to Lambda probe.
• ‒ Check probe heating at Lambda probe connector contacts 1+2 for continuity
       Specification: max. 22 ω

If the specification is not obtained:

• ‒ Renew Lambda probe (G39).

If the specification is attained:

• ‒ Start engine and run at idling speed.
• ‒ → Connect multimeter to measure voltage at contacts 1+2 of connector.
       Specification: approx. battery voltage
• ‒ Switch off ignition

If no voltage is present:

• ‒ Check wiring from contact 1+2 to relay plate according to current flow diagram.