Audi Workshop Service and Repair Manuals

Notes:

• ◆ The actual knock sensors 1 and 2 -G61 and -G66 cannot be electrically checked (interrogate fault memory ).
• ◆ Exact compliance with tightening torque of 20 Nm is essential to proper knock sensor operation.
• ◆ Check connector for corrosion.
• ◆ Exclusive use is to be made of gold-plated contacts when repairing contacts in knock sensor connector.
• ◆ Check connector between knock sensor and wiring harness for corrosion.

Checking knock sensors

Fitting location of connectors => Page 24-5

• ‒ Unplug connector of appropriate knock sensor in engine compartment.

• ‒ → Check all three contacts at knock sensor connector for mutual short circuit (contacts 1+2, 1+3, 2+3).

• Specification: No mutual contact between wires (infinity ohms)

• ‒ Replace knock sensor if there is contact.
• ‒ Check knock sensor wiring if no short circuit is found.

Checking wiring between knock sensors and engine control unit

• ‒ Connect test box V.A.G 1598/31 to engine control unit wiring harness. Actual engine control unit is not to be connected.
• ‒ → Check wiring between respective sensor connector ...
• ‒ ... to engine control unit for open circuit and short to positive/earth.

Knock sensor 1 -G61 (cylinders 1 and 2)

Knock sensor 2 -G66 (cylinders 3 and 4)

• Resistance: max. 1.5 ohms

=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder

• ‒ If necessary, eliminate open circuit in wiring/short circuit.