Knock Sensor 2 Circuit High (Bank 2)
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.
- Keep driving?
- Short distances only
- DIY difficulty
- moderate
- Estimated cost
- $150 - $600 (parts and labor)
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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
-
Check knock sensor 2 torque specification -- overtightening is a common cause of high output
-
Listen for abnormal mechanical noises from bank 2 (rod knock, piston slap, exhaust leak)
-
Check for short to voltage in the knock sensor 2 signal wire
-
Compare knock sensor 2 voltage readings to knock sensor 1 at idle
-
Replace the sensor and torque to exact specification if tests confirm sensor failure
Common Fixes by Vehicle
What techs usually find when diagnosing P0333 on specific vehicles — tap your vehicle for the fix and the exact part:
1999-2014 GM V8 & Toyota/Lexus moderate DIY
Knock sensor 2 circuit high on bank 2 — same failure family as P0328. On GM trucks, do both knock sensors and the harness together since they fail from the same moisture intrusion under the intake. On other makes, check the bank 2 sensor connector and resistance before replacing.
Labor: 1-3 hoursFrequently 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.
Sources
This page is built from documented references. Verify against your own service info before repair work.
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