P0328 — Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)
Drive with caution — fix soon.
What P0328 means
This code means the voltage from the knock sensor is reading lower than expected, often near zero. It usually points to a shorted or open sensor circuit, a failed knock sensor, or damaged wiring. The fix typically involves checking the wiring for shorts to ground and replacing the knock sensor if it has failed.
Common symptoms
- Check engine light is on
- Slight loss of power
- Reduced fuel economy
- Possible engine pinging under load
- Otherwise mostly normal driving
Common causes
- Failed knock sensor
- Short to ground in the sensor wiring
- Open circuit in the sensor wiring
- Corroded or loose connector
- Engine control module fault
Typical repair cost
$150 – $500
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0328 code?
Usually yes, for short trips. The engine runs, but it may not be fully protected from detonation. Go easy on the throttle and get it diagnosed within a week.
How much does it cost to fix a P0328 code?
Generally $150 to $500. The sensor part is often affordable, but labor can climb if the sensor is buried under the intake manifold.
Is a P0328 code serious?
It's moderate. There's no immediate breakdown, but without a working knock sensor the engine loses protection from harmful detonation over time.
What does low input mean for a P0328 code?
It means the sensor's voltage signal is reading too low, often near zero. This usually points to a short to ground, a broken wire, or a failed sensor.