P0328
Knock/Combustion Vibration Sensor A Circuit High
Ignition / knock control
Generic OBD-II
Medium
What it means
P0328 means the knock sensor "A" signal is reading higher than the valid range. The knock sensor lets the ECM detect engine knock (detonation) and pull ignition timing to protect the engine; with the signal faulted, the ECM defaults to more conservative timing, costing a little power and economy. It's usually the sensor or its wiring — often a short to voltage on the signal wire.
Medium
Can I keep driving? Yes — the car drives, but with the knock sensor out the ECM pulls timing as a precaution, so expect slightly reduced power and economy.
Common symptoms
What you'll notice
- Check-engine light on
- Reduced power and throttle response
- Slightly reduced fuel economy
- Possible engine knock or pinging under load
Common causes
Most likely first
- Faulty knock sensor — most commonLikely
- Damaged, corroded, or shorted wiring/connector in the sensor circuitCommon
- Signal wire shorted to voltage (drives the reading high)Common
- Poor sensor groundLess often
- Faulty ECM (rare)Less often
How to diagnose & fix
Work through it in order
- Read freeze-frame data and note whether the high-signal fault is constant or intermittent.
- Locate the knock sensor (usually on the engine block) and inspect its connector and wiring for damage or corrosion.
- Check for a short to voltage on the signal wire and verify a clean sensor ground.
- Measure the sensor's resistance/output against spec; replace it if out of range.
- Clear the code and road-test; confirm timing is no longer being pulled.
FAQ
Quick answers
Is it safe to drive with P0328?+
Yes, short term. To stay safe the ECM retards ignition timing, which costs a little power and economy. Fix it so knock protection works normally again.
Can I just clear P0328?+
It returns once the circuit reads high again. The sensor or its wiring needs repair.
Related codes
Often seen with P0328
Read & clear P0328 yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.
✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX