What this code means

The ECU detected an internal fault in its knock control processing circuit. The knock sensor input is not being properly processed by the ECU, compromising engine knock protection.

Symptoms

• Check Engine Light
• Engine may run with reduced power
• Possible engine knock under load
• Safety timing retard applied

Common causes

• ECU internal knock processing circuit failure
• Knock sensor wiring interference
• Poor ECU ground connection
• Electrical noise from aftermarket components
• ECU damage from voltage spike

Diagnostic steps

1. Check knock sensor wiring for electromagnetic interference
2. Inspect ECU ground connections
3. Remove aftermarket electrical components temporarily
4. Test knock sensor signal quality
5. Consider ECU replacement if fault is internal

Repair notes

Address external interference sources first; replace ECU if internal circuit has failed.

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