Knock/Combustion Vibration Sensor A Circuit Low
What it means
P0327 means the knock sensor's circuit is producing a low (or open) signal voltage. The knock sensor listens for detonation so the ECM can retard ignition timing to protect the engine. With a low signal, the ECM can't trust the sensor and typically pulls timing as a precaution — the car keeps running but may feel a little softer and use slightly more fuel. It's usually a bad sensor or wiring, not the engine itself.
Can I keep driving? Safe to drive — the car runs, but the ECM may pull timing as a precaution, softening performance and economy; fix it to restore full spark timing.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power or sluggish acceleration (ECM retards timing defensively)
- Slightly worse fuel economy
- Possible engine knock or ping under load if timing isn't protected
Common causes
Most likely first
- Failed knock sensor giving a low/open signal — most commonLikely
- Damaged wiring or a poor connection in the knock-sensor circuitCommon
- Loose or corroded sensor connectorCommon
- Rarely, an ECM faultLess often
How to diagnose & fix
Work through it in order
- Inspect the knock-sensor connector and wiring for damage, corrosion, or an open — a common cause of a low signal.
- Measure the sensor's resistance and compare to the service-manual spec.
- Confirm the sensor is torqued correctly to the block; a loose sensor reads poorly.
- Replace the knock sensor if it's out of spec, then clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0327?+
Can I just clear P0327?+
Related codes
Often seen with P0327
Read & clear P0327 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.