What Does P0328 Mean?
Knock sensor 1 on Bank 1 is reporting a voltage higher than the maximum threshold expected by the PCM. This can indicate a shorted sensor, excessive engine mechanical noise being interpreted as knock, or an electrical issue in the wiring. The PCM may excessively retard ignition timing due to the perceived knock, causing significant power loss and poor fuel economy.
Common Causes
25%
Internal short in the knock sensor producing elevated voltage output
25%
Actual engine mechanical problem creating excessive vibration at knock frequencies (rod bearing wear, piston slap)
20%
Short to voltage in the knock sensor signal wire from chafed insulation
15%
Knock sensor over-torqued, making it overly sensitive to normal engine vibrations
15%
Electromagnetic interference coupling into the knock sensor circuit from ignition or charging system
Diagnostic Steps
1
Monitor knock sensor voltage and knock retard PIDs — if knock retard is consistently high (>5 degrees) even under light load, the PCM is reacting to a false high signal.
2
Listen for actual mechanical engine noises with a stethoscope on the lower block near each cylinder. Distinct knocking at rod bearing locations indicates real mechanical damage, not a sensor fault.
3
Disconnect the knock sensor and check the PCM-side reading — it should go to a stable low value. If it remains high, there is a wiring short to voltage.
4
Inspect the knock sensor wiring for chafing against hot or powered components. Check that the shield drain wire is not contacting a power source.
5
Remove and reinstall the knock sensor at the correct torque specification with a new washer. Excessive torque over-stresses the piezo element and causes high output.
Estimated Repair Cost
$100 - $600
Parts + labor, varies by vehicle and location
Knock sensor 1 on Bank 1 is reporting a voltage higher than the maximum threshold expected by the PCM. This can indicate a shorted sensor, excessive engine mechanical noise being interpreted as knock, or an electrical issue in the wiring. The PCM may excessively retard ignition timing due to the per...
The most common cause of P0328 (Knock Sensor 1 Circuit High Input (Bank 1 or Single Sensor)) is: Internal short in the knock sensor producing elevated voltage output
Typical repair costs for P0328 range from $100 to $600, depending on the vehicle, location, and whether you do it yourself or go to a shop.
If the high signal is due to actual engine mechanical damage (rod knock), stop driving immediately — continued operation risks catastrophic engine failure. If it is a sensor/wiring issue, the vehicle is safe to drive but will have reduced power from excessive timing retard. Have the cause diagnosed promptly to rule out mechanical damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0328 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition / Knock Control System
Difficulty
Type
Generic (SAE)
Recommended Tools
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