What it means
The knock sensor signal voltage is above the expected range. Often caused by a sensor producing excess output due to mechanical noise (loose mounting, accessory drive vibration) rather than a sensor fault.
At a glance
- Usually lights the check-engine light
- Affects emissions; the car can fail an emissions test
How it works
Knock sensor 1 on bank 1, or the single sensor, converts engine vibration into a signal the control module uses to manage ignition timing. P0328 sets when the signal is higher than expected; mechanical vibration, a signal wire shorted to supply voltage, or a failed sensor can cause the high reading.
Common causes
Most likely first.
- Mechanical noise picked up by sensor (loose accessory)
- Signal wire shorted to supply voltage
- Sensor failed
Symptoms
- Check engine light on
- Power loss from defensive spark retard
- Increased fuel consumption
- Possible audible pinging under load
How to diagnose it
- Review freeze-frame and live data to confirm the high knock-sensor signal and note the engine speed and load when it occurs.
- Inspect knock sensor 1 on bank 1, or the single sensor, and its connector and wiring for damage, corrosion, or a loose fit.
- Check for abnormal mechanical vibration, including a loose accessory or accessory-drive component that could transmit noise to the sensor.
- Test the signal wire for a short to supply voltage and check its routing for chafing using the circuit diagram.
- If wiring and mechanical checks do not explain the signal, test the sensor according to the manufacturer's procedure.
Common fixes
- Secure or repair a loose accessory or other identified source of vibration.
- Repair wiring shorted to supply voltage or damaged insulation.
- Clean or repair a corroded sensor connector.
- Replace knock sensor 1 on bank 1, or the single sensor, if it fails testing.
Can I keep driving?
Avoid heavy acceleration and towing until diagnosed because the module may retard timing, reducing power and fuel economy. If you hear persistent pinging under load, ease off and stop driving if it continues.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.