Knock sensor control limit, checking

WARNING: This page is about a different car, the 2004 Audi A6, 2003 Audi A6, 2002 Audi A6, 2001 Audi A6, and 2000 Audi A6. However, it is still accessible from the selected car via links, so may be relevant.

If the malfunction message "Knock Control - Limit Attained" is recorded in the DTC memory the following tests must be carried out:

KNOCK SENSOR SYMPTOM CHART

	Possible cause of malfunction	Corrective action
Malfunction message relating to all cylinders or malfunction message relating to all cylinders in one bank	Poor fuel quality	Change to higher quality fuel (see Owner's Manual)
	Incorrect tightening torque on knock sensor	Loosen knock sensor, then tighten to 20 Nm (15 ft lb)
	Knock sensor faulty	Check knock sensor. See KNOCK SENSOR (KS) 1 -G61- AND KNOCK SENSOR (KS) 2 -G66-, CHECKING .
	Corrosion on connector
	Loose components on engine	Secure loose components
Malfunction message relating to one cylinder	Mechanical engine damage	Check compression pressure
Malfunction message relating to one cylinder	Loose components on engine	Secure loose components