Knock Sensor 1 Circuit Low (Bank 1 or Single Sensor)
The knock sensor produces a small voltage from engine vibrations. The ECU uses it to tell whether there is knocking and to retard the ignition.
What the car has detected
The sensor voltage is too low: it may be a wire shorted to earth or open, or a sensor badly tightened or damaged.
The ECU retards the ignition to be safe and the car has less power. If you hear metallic knocking when accelerating, do not push the engine.
Symptoms
- Engine warning light on
- Less power or jerking
- Rough idle in some cases
Possible causes
- Sensor wire shorted to earth or broken
- Knock sensor badly tightened or damaged
- Faulty engine ECU, in rare cases
Checks for the garage
- Check the sensor’s tightening torque
- Check the sensor wiring and connector
- Check the sensor and the knock control with the diagnostic tool
Next step
Ask for the knock sensor to be tightened to its torque and its wiring checked before it is replaced.
Go to a garage in the next few days. Use the fuel the maker specifies meanwhile.