Knock Sensor Circuit Malfunction
Table of contents
- Possible Causes
- How To Fix
- Tech Notes
- Cost To Diagnose
- When is the code detected
- Possible Symptoms
- Description
P0325 Possible Causes
- Faulty Knock Sensor
- Knock Sensor circuit poor electrical connection
- Knock Sensor harness is open or shorted
- Faulty Engine Control Module (ECM)
How do I fix code P0325?
Check the “Possible Causes” listed above. Visually inspect the related wiring harness and connectors. Check for damaged components and look for broken, bent, pushed out, or corroded connector’s pins.
Tech Notes
User Submitted Video
Cost of diagnosing the P0325 code
The cost of diagnosing the P0325 code is 1.0 hour of labor. The auto repair labor rates vary by location, your vehicle’s make and model, and even your engine type. Most auto repairs shops charge between $75 and $150 per hour.
When is the code detected
When an excessively low or high voltage from the sensor is sent to Engine Control Module (ECM)
Possible Symptoms
- Engine Light ON (or Service Engine Soon Warning Light)
- Possible Lack/Loss of Power
P0325 Description
A knocking vibration from the cylinder block is sensed as vibrational pressure by the Knock Sensor. This pressure is converted into a voltage signal and sent to the Engine Control Module (ECM). The ECM uses this signal to retard the ignition timing and protect the engine from this damaging pre-ignition.
Engine knock occurs within a specific frequency range. The Knock Sensor, located in the engine block, cylinder head, or intake manifold, is tuned to detect that frequency.
Inside the knock sensor is a piezoelectric element. Piezoelectric elements generate a voltage when pressure or vibration is applied to them. The piezoelectric element in the Knock Sensor is tuned to the engine knock frequency.
The vibration from the engine knocking vibrates the piezoelectric element generating a voltage. The voltage output from the Knock Sensor is highest at this time.