OBD-II code · Powertrain (generic)
P033C Knock/Combustion Vibration Sensor D Circuit Low
Knock sensor D signal below lower plausibility — short to ground. Wiring faults of this kind typically come from chafing, water ingress at connector seals, or pin push-back — a wiggle test on the harness while the code is active often confirms the location.
Is it safe to drive with P033C?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyShort to ground
- Less likelyGateway module routing CAN messages incorrectly
- Less likelyCAN terminating resistor (120 Ω) drifted out of spec
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2 h
- Emissions test
- Likely to fail
- Parts involved
- Knock Sensor
Related codes
- P032CKnock/Combustion Vibration Sensor C Circuit Low
- P0339Crankshaft Position Sensor A Circuit Intermittent
- P033AKnock/Combustion Vibration Sensor D Circuit
- P033BKnock/Combustion Vibration Sensor D Circuit Range/Performance
- P033DKnock/Combustion Vibration Sensor D Circuit High
- P033EKnock/Combustion Vibration Sensor D Circuit Intermittent
- P033FCrankshaft/Camshaft Loss Of Synchronization
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.