Knock Sensor 1 Circuit (Bank 1 or Single Sensor)
The knock sensor “listens” to engine vibrations to detect knocking (uncontrolled combustion that can damage the engine). If it detects it, the engine computer retards the ignition. This code means a fault in that sensor's circuit.
What the car has detected
The knock sensor signal is missing or the circuit is open, shorted to earth or shorted to voltage.
To protect itself, the engine computer usually retards the ignition as far as it can: the engine loses power and uses more fuel, but keeps running. Avoid pushing it and have it checked soon, because without the sensor it can't detect real knocking.
Symptoms
- Engine warning light on
- Loss of power
- Higher fuel consumption
- Uneven running in some cases
Possible causes
- Sensor wiring shorted to earth or voltage, or open circuit
- Loose or corroded connector
- Damaged sensor or one not tightened correctly on the block
- Engine computer fault (rare)
Checks for the garage
- Inspect the sensor, connector and wiring for corrosion or damage
- Check the sensor is tightened to the correct torque
- Measure the circuit's insulation to earth with the engine computer disconnected
- Test the sensor per the manual and look at its signal with diagnostics
- Replace the engine computer only if the circuit and sensor are fine
Next step
Have the knock sensor connector, wiring and tightness checked before replacing it.
Go to a garage if the code comes back or you notice a loss of power. The sensor is usually on the engine block and testing it needs electrical measurements.