P0326
Knock/Combustion Vibration Sensor A Circuit Range/Performance
Ignition timing
Generic OBD-II
Medium
What it means
P0326 means the knock sensor's signal is outside the range the ECM expects. That sensor listens for engine knock so the computer can trim ignition timing; when its signal is unreliable, the ECM retards timing conservatively and you may lose a little power. This is a sensor-circuit fault — it does not stop the engine from starting or running.
Medium
Can I keep driving? Usually driveable — the ECM retards timing as a precaution, so expect slightly less power and economy but no immediate risk to a healthy engine.
Common symptoms
What you'll notice
- Check-engine light on
- Slightly reduced power or acceleration
- Audible knocking or pinging under load (timing can no longer be trimmed accurately)
- Small drop in fuel economy
Common causes
Most likely first
- Failed knock sensor or one reading out of rangeLikely
- Damaged wiring or connector in the sensor circuitCommon
- Loose or corroded electrical connectionCommon
- Genuine engine knock (carbon build-up, low octane, lean condition) the sensor is reportingLess often
- ECM fault (rare — rule out sensor and wiring first)Less often
How to diagnose & fix
Work through it in order
- Scan and read freeze-frame data to confirm the fault is the knock-sensor circuit's signal, not a mechanical knock.
- Inspect the sensor connector and wiring — these sensors sit on the block and their harness is prone to heat and chafing.
- Check the knock sensor's resistance and mounting torque against spec.
- Rule out real detonation from low-octane fuel, carbon, or a lean mixture.
- Replace the knock sensor if it is out of range with good wiring. Clear and re-test.
FAQ
Quick answers
Is it safe to drive with P0326?+
Generally yes, short-term. The ECM pulls timing to protect the engine, so you lose a little power. Fix it before hard driving or towing.
Can I just clear P0326?+
It will return once the ECM re-tests the knock circuit. This is a sensor/wiring fault that needs repair, not just a reset.
Related codes
Often seen with P0326
Read & clear P0326 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