Knock Sensor 2 Circuit Low Input (Bank 2)
Knock sensor 2 (bank 2) reports a signal level below the diagnostic threshold. The sensor is a piezo element bolted to the engine block; output should be a small AC voltage on each combustion event. A cold or open sensor reads 0 V; a loose mounting bolt damps the signal. Without knock detection, the ECM retards spark globally as a safety measure — fuel economy and power suffer.
Affected components
- Knock sensor
- Sensor wiring
Common causes
- High likelihood: Knock sensor failed
- Medium likelihood: Signal wire shorted to ground
- Low likelihood: Connector pins corroded - high contact resistance
Possible symptoms
- Check engine light on
- Power loss from defensive spark retard
- Increased fuel consumption
- Possible audible pinging under load
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
- A drive cycle may be required after repair
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.