Knock Sensor 2 Circuit High (Bank 2)
What does P0333 mean?
The P0333 code means the vehicle's onboard diagnostic system has detected: Knock Sensor 2 Circuit High (Bank 2). This is a moderate severity code.
Common Symptoms
- Check Engine Light illuminated
- Excessive timing retard on bank 2
- Significant power loss
- Poor fuel economy
- Engine feels sluggish
Probable Causes (Ranked by Likelihood)
- Knock sensor 2 overtightened Very High
- Engine mechanical noise on bank 2 generating false knock signals High
- Short to voltage in knock sensor 2 signal wiring High
- Faulty knock sensor producing excessive output Moderate
- Exhaust leak near bank 2 creating false knock vibration Moderate
Step-by-Step Diagnostic Procedure
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Check knock sensor 2 torque specification -- overtightening is a common cause of high output
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Listen for abnormal mechanical noises from bank 2 (rod knock, piston slap, exhaust leak)
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Check for short to voltage in the knock sensor 2 signal wire
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Compare knock sensor 2 voltage readings to knock sensor 1 at idle
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Replace the sensor and torque to exact specification if tests confirm sensor failure
Frequently Asked Questions
Can I drive with code P0333?
You can drive short distances, but power loss will be noticeable. The PCM heavily retards bank 2 timing to protect the engine. Diagnose promptly to rule out actual mechanical knock.
Can a loose heat shield cause a high knock sensor reading?
Yes. A rattling heat shield near the engine block can transmit vibrations that the knock sensor interprets as engine detonation, causing a false high signal.
What is the correct torque for a knock sensor?
It varies by manufacturer, typically between 15-25 ft-lbs. Always consult the service manual for your specific vehicle. Using a torque wrench is essential -- do not estimate by feel.