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Home >> Audi >> 2004 >> A8 >> Repair and Diagnosis (Single Page) >> Engine Mechanical >> Cooling Fan >> 4.2L - Generic Scan Tool, Engine Code(S): BFM >> 28 - Ignition/Glow Plug System >> Ignition System, Checking >> Knock Sensor Control >> Knock Sensor Control
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Knock Sensor Control

Possible cause of malfunction if knock control (ignition angle retardation, injection quantity limit) is activated.

Possible cause Corrective action
Poor fuel quality Change fuel quality (→ operating instructions)
Knock sensor tightened to incorrect torque Loosen knock sensors and tighten to 20 Nm
Knock sensor faulty Check knock sensor → Knock Sensors, Checking .
Corrosion at harness connector  
Engine components loose Secure engine components
Engine damage Check compression pressure
Engine components loose Secure engine components