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 sequence

Engine codes ADY and AGG

• ‒ → Separate brown 3 pin connector to knock sensor 1 (G61) -1-.

Engine code AFT

• ‒ → Separate blue 3 pin connector -2- to knock sensor 1 (G61) -1-.

Continued for all engine codes

• ‒ Connect multimeter with aux. cables from V.A.G 1594 to measure resistance at contacts 1+2, 1+3 and 2+3 on connector to knock sensor.
       Specification ∞ω

If the specification is attained:

• ‒ → Connect test box V.A.G 1598/18 to control unit wiring loom.

Engine codes ADY and AGG

• ‒ → Check wiring between test box and 3 pin connector for open circuit according to current flow diagram.
       Contact 1+socket 36
       Contact 2+socket 34
       Contact 3+socket 09
       Wire resistance: Max. 1.5 ω

Engine code AFT

• ‒ → Check wiring between test box and 3 pin connector for open circuit according to current flow diagram.
       Contact 1+socket 36
       Contact 2+socket 34
       Contact 3+socket 09
       Wire resistance: Max. 1.5 ω

Continued for all engine codes

• ‒ Additionally check wires for short to one another.
       Contact 3+socket 34
       Contact 3+socket 36
       Contact 2+socket 36
       Specification: ∞ω

If no wiring fault is detected:

• ‒ Loosen knock sensor and tighten again to 20 Nm.
• ‒ Carry out test drive.

• During the road test the following operating conditions must be fulfilled:
• ‒ The coolant temperature must exceed 80 °C .
• ‒ When the temperature is reached, the operating conditions
       Idling
       Part throttle
       Full throttle
       Overrun
  must be attained several times.
• ‒ At full throttle the speed must exceed 3500 rpm.

• ‒ Again interrogate the control unit fault memory.

If the fault is still present:

• ‒ Replace knock sensor (G61) =>Page 28-3 , item 10 .