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.

Real-world scan data

Seen in

1,548

scans in the past year

Found in

0.2%

of scans

0.4%

of scans that found faults

Appears alongside · share of P0328 scans

P0327in 26.0% of scans

P0500in 21.8% of scans

P0133in 18.7% of scans

Figures reflect only diagnostic scans recorded through our own apps and tools. Cars are typically scanned because a symptom or warning light prompted it, so these counts describe our scan records — not the incidence of faults in any model, and not the quality, reliability, or safety of any vehicle. No comparison between manufacturers or models is implied. All trademarks belong to their respective owners; no affiliation or endorsement is implied.

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.

Read & clear P0328 yourself

Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.

▶ Get it on Google Play

✓ Verified name — SAE J2012 / ISO 15031-6Guidance reviewed by OBD DashX