Checking knock sensors -G61, -G66 and -G198: Audi 4.2 (BCY, BRV)
Step-by-step checking knock sensors -G61, -G66 and -G198 for the Audi 4.2 (BCY/BRV): factory workshop text.
Workshop procedure for AUDI — the factory write-up, straight from real workshop data.
📋 Procedure
ℹ️ Torque figures below come verbatim from workshop data — always cross-check against your vehicle's factory manual before final tightening.
BRV
Notes:
The V8 biturbo engine is fitted with a total of three knock sensors.
Cylinders 1, 2, 3 and 4 are monitored by knock sensor 1 -G61. Cylinders 5 and 6 are monitored by knock sensor 2 -G66. Cylinders 7 and 8 are monitored by knock sensor 3 -G198.
The actual knock sensors -G61, -G66 and -G198 cannot be electrically tested (interrogating fault memory => Page
01-12
).
Exact compliance with tightening torque of 20 Nm is essential to proper knock sensor operation.
Exclusive use is to be made of gold-plated contacts when repairing contacts in knock sensor connectors.
Check connector between knock sensor and wiring harness for corrosion.
Checking knock sensor wiring
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 up test box V.A.G 1598/31 at wiring harness to engine control unit. Actual engine control unit is not to be connected=>Page
24-34
.
Check wiring between respective sensor connector ...
... and engine control unit for open circuit and short to positive/earth.
Knock sensor 1 -G61
3-pin connector at wiring harness, socket · Test box V.A.G 1598/31, socket
1 (earth) · 99
2 (signal) · 106
3 (screen) · 108
Knock sensor 2 -G66
3-pin connector at wiring harness, socket · Test box V.A.G 1598/31, socket
1 (earth) · 99
2 (signal) · 107
3 (screen) · 108
Knock sensor 3 -G198
3-pin connector at wiring harness, socket · Test box V.A.G 1598/31, socket
1 (earth) · 99
2 (signal) · 31
3 (screen) · 108
Resistance: max. 1.5 ohms
Eliminate open circuit in wiring/short circuit if necessary.
=> Current Flow Diagrams, Electrical Fault-finding and Fitting Locations binder
If there is neither an open circuit in the wiring nor a short circuit, replace engine control unit
=> Page
24-38
.
TorqFix answers live for your specific car — tell it the engine code and it serves the matching sequence, torque figures and wiring for that exact variant.
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Who makes these pages, and how
TorqFix was built by a mechanic — after a 2,700 km drive with five roadside repairs that no diagnostic tool could explain.
The figures on this page come from manufacturer workshop documentation and are shown as they are. The page is assembled automatically from that data — it is not written by an AI. The AI works in the chat, where it answers for your specific car. It writes nothing here.
Variants of the same model differ. Cross-check torque against the factory manual for your engine before final tightening.
Seen a figure that does not match your manual? Write to us — we correct it and note when. support@torqfix.com
The story behind TorqFix →Workshop data on this page last updated 20 Sep 2026.