P0332
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.
- Check engine light: Yes
- Emissions related: Yes
- Repair difficulty: hard
Symptoms
- Check engine light on
- Power loss from defensive spark retard
- Increased fuel consumption
- Possible audible pinging under load
Common causes
Ordered by how often each turns out to be the cause.
- Knock sensor failedCommon
- Signal wire shorted to groundPossible
- Connector pins corroded - high contact resistanceLess likely
Parts involved
- Knock Sensor
- Sensor Wiring
P0332 is a generic OBD-II code defined by SAE J2012. Exact wording and diagnostic procedure vary by manufacturer and model. Code definitions are drawn from the public-domain OBDex dataset; the workshop notes are our own.