Safety Warning
DIY auto repair can cause serious injury, fire, or vehicle damage. These guides are for informational purposes only. Always follow OEM torque specs, wear PPE, and consult a certified mechanic if you are unsure. You are solely responsible for your safety.
Knock Sensor (KS) , Checking
2005 Audi A6 3.2 TSECTION Knock Sensor (KS) , Checking
WARNING: This page is about a different car, the 2009 Audi A4, 2008 Audi A4, 2007 Audi A4, 2006 Audi A4, and 2005 Audi A4. However, it is still accessible from the selected car via links, so may be relevant.
The following procedure is used to check Knock Sensor (KS) 1 G61 and Knock Sensor (KS) 2 G66.
Special tools, testers and auxiliary items required
- Multimeter.
- Wiring diagram.
NOTE:
- Cylinders 1, 2, and 3 (bank 1) are monitored by Knock sensor (KS) 1 -G61-. Cylinders 4, 5, and 6 (bank 2) are monitored by Knock sensor (KS) 2 -G66-.
- Knock sensors themselves cannot be checked electrically.
- When servicing terminals in the harness connector of knock sensors, use only gold-plated terminals.
- For the knock sensors to function properly, it is important that the tightening torque be exactly 20 Nm.
- Contact surfaces between Knock Sensor (KS) 1 G61 and Knock Sensor (KS) 2 G66 and cylinder block must be free of corrosion, dirt and grease.
Test requirements
- The mounting bolt of Knock Sensor (KS) 1 G61/Knock Sensor (KS) 2 G66 tightened to 20 Nm.
- The Engine Control Module (ECM) J623 fuses OK.
- Battery voltage at least 12.5 volts.
- All electrical consumers such as, lights and rear window defroster, switched off.
- Vehicles with automatic transmission, shift selector lever into position "P" or "N".
- A/C switched off.
- Ground (GND) connections between engine/transmission/chassis OK.
- Ignition switched off.
Test procedure
- Perform a preliminary check to verify the customers complaint. Refer to → General Diagnosis .
Start diagnosis
- Remove the rear engine cover - arrows -.
Checking knock sensor and wiring
NOTE:
- The knock sensor electrical connectors can be identified by color. Knock Sensor (KS) 1 -G61- (Bank 1) is green. Knock Sensor (KS) 2 -G66- (Bank 2) is gray.
RENDER: 1.0x
NO RELATED
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When to See a Mechanic
Stop DIY work and contact a certified mechanic immediately if any of the following apply:
- • You smell fuel, burning insulation, or see smoke.
- • Brakes feel soft, pull hard to one side, or make grinding noises.
- • The engine overheats, stalls repeatedly, or misfires under load.
- • You are missing required tools, torque specs, or safe lifting equipment.
- • You are not confident in the next step or safety outcome.