What does P0325 mean?
The knock sensor is a small microphone bolted to the engine block. It listens for detonation (pinging) so the computer can pull ignition timing back before damage occurs.
The computer has detected an electrical fault in this sensor circuit.
Codes are a starting point. They tell you which test failed, not which part to replace. Check for other stored codes and fix those in a sensible order.
Symptoms
- Check engine light
- Reduced power or fuel economy (timing pulled back)
- Pinging under load if there is real knock
Common causes
- Open or shorted wiring
- Corroded connector
- Failed sensor
How to diagnose P0325
- Inspect connector and harness.
- Check the signal with a meter or scope.
- Replace the sensor after wiring checks out.
- Check sensor and wiring resistance against spec.
- Inspect the harness, which is often chewed by rodents or damaged by coolant leaks.
How to fix it
- Repair wiring
- Replace the knock sensor
Estimated repair cost
Likely repairs for P0325 run from about $100 to $600, depending on the cause.
| Repair | Typical range (parts + labor) |
|---|---|
| Diagnostic fee (scan + testing) | $100 - $200 |
| Knock sensor replacement | $150 - $600 |
| Wiring/connector repair | $100 - $400 |
These are rough US estimates for an independent shop in 2026, based on typical parts prices and standard labor times. Dealers, big trucks, luxury brands and high-cost areas often run higher. They are not quotes. Use the repair cost estimator to adjust for your vehicle.
How serious is P0325?
Moderate severity
Usually safe to drive gently. Avoid heavy loads, and use the right fuel octane.
P0325 FAQ
What does P0325 mean?
P0325 stands for "Knock Sensor 1 Circuit (Bank 1 or Single Sensor)". The knock sensor is a small microphone bolted to the engine block.
Can I drive with a P0325 code?
Usually safe to drive gently. Avoid heavy loads, and use the right fuel octane.
How much does it cost to fix P0325?
It depends on the cause. The likely repairs for P0325 range from about $100 to $600 at an independent shop in the US, plus a diagnostic fee of roughly $100-$200. These are rough estimates; dealer prices and some vehicles run higher.
What is the most common cause of P0325?
The most common causes are: open or shorted wiring; corroded connector; failed sensor.