P0333
Knock Sensor 2 Circuit High (Bank 2)
- Severity
- Medium
- Driving
- Drivable — book it in
The knock sensor 2 signal is reading high - typically shorted to voltage or with a lost earth. The module cannot trust it, retards ignition timing as a precaution, and the engine loses power.
Possible causes
- CommonFailed knock sensor
- CommonSensor loose, or tightened to the wrong torque - these only work when clamped correctly to the block
- CommonCorroded connector or damaged wiring
- PossibleGenuine engine noise the sensor is correctly hearing - worn bearings, a loose component, or detonation from poor fuel
- PossibleWiring routed against the engine, picking up interference
- RareFailed control module input
What you might notice
- Noticeably less power, especially under load or up hills
- Worse fuel economy
- Pinging or knocking under acceleration
- Check engine light on
- Often no symptom beyond the light
What to check, in order
- Check the sensor earth before assuming a shorted signal wire.
- Understand what has been lost. The module listens for knock and retards ignition timing when it hears it; without a trustworthy sensor it retards timing as a precaution, which is why the car feels flat rather than sounding wrong.
- Check the sensor is tight and correctly torqued. These sensors read vibration through their mounting, so a loose one or one tightened wrongly reports nonsense while looking perfect.
- Inspect the connector and wiring - the harness runs across a hot engine.
- Try a tank of the fuel grade the manufacturer specifies. Genuine detonation from low-octane fuel makes a working sensor report knock, and that is not a fault.
- Find out where the sensor is before committing. On many V engines it sits under the intake manifold, and the labour costs far more than the part.
Read this code from your own car
Plug an ELM327 adapter into the OBD-II port under the dashboard. Pin16 reads every stored, pending and permanent code, explains each one like this page does — offline, with no account — and shows what the car recorded when the fault was set.
Where this code sits
P00xxP01xxP02xxP03xxP04xxP05xxP06xxP07xxP08xxP09xxP0AxxP0BxxP0CxxP0DxxP0ExxP0FxxP10xxP11xxP12xxP13xxP14xxP15xxP16xxP17xxP18xxP19xxP1AxxP1BxxP1CxxP1DxxP1ExxP1FxxP20xxP21xxP22xxP23xxP24xxP25xxP26xxP27xxP28xxP29xxP2AxxP2BxxP2CxxP2DxxP2ExxP2FxxP30xxP31xxP32xxP33xxP34xxP35xxP36xxP37xxP38xxP39xxP3AxxP3BxxP3CxxP3DxxP3ExxP3Fxx
Ignition system or misfire
P0300P0301P0302P0303P0304P0305P0306P0307P0308P0309P0310P0311P0312P0313P0314P0315P0316P0317P0318P0319P0320P0321P0322P0323P0324P0325P0326P0327P0328P0329P0330P0331P0332P0333P0334P0335P0336P0337P0338P0339P0340P0341P0342P0343P0344P0345P0346P0347P0348P0349P0350P0351P0352P0353P0354P0355P0356P0357P0358P0359P0360P0361P0362P0363P0364P0365P0366P0367P0368P0369P0370P0371P0372P0373P0374P0375P0376P0377P0378P0379P0380P0381P0382P0383P0384P0385P0386P0387P0388P0389P0390P0391P0392P0393P0394