P0325 Knock sensor A circuit (bank 1 or single sensor)
What P0325 means
The engine computer has a problem with the signal from knock sensor A (bank 1, or the only knock sensor). This sensor listens for detonation so the computer can retard ignition timing before damage occurs. Without it, the computer retards timing as a precaution, which costs power and fuel.
P0325 is a generic SAE J2012 code: it means the same on every make. The exact cause still depends on the car, so read the freeze-frame data before replacing parts.
At a glance
- Severity
- Medium
- Typical repair cost
- 80–300 €
- Workshop time
- 1.5–6 h
- Repair difficulty
- Hard
- DIY possible
- No
- Check engine light
- Yes
- Affects emissions test
- Yes
Parts and labour at an independent workshop in Europe. Main dealers charge more; the cause decides the bill, not the code.
Symptoms
- Check engine light on
- Reduced power from retarded ignition timing
- Higher fuel consumption
- Possible audible pinging under load
Common causes
- Failed knock sensor
- Damaged wiring or connector, often routed under the intake manifold
- Sensor loose or not tightened to the correct torque
- Corrosion between the sensor and the engine block
Can I keep driving with P0325?
You can drive, but have it checked within one to two weeks. Use the correct fuel grade and avoid heavy load or full throttle, because knock protection is reduced.
What to check first
- Check the knock sensor connector and wiring for damage, corrosion and oil contamination.
- Make sure the sensor is tightened to the specified torque on a clean mounting surface.
- Measure the sensor resistance and check the wiring back to the engine computer for continuity.
- Replace the sensor if it is out of specification.
Related codes
- P0326 Knock sensor A circuit range/performance (bank 1 or single sensor)
- P0327 Knock sensor 1 circuit low (bank 1 or single sensor)
- P0328 Knock sensor A circuit high (bank 1 or single sensor)
- P0320 Ignition/distributor engine speed input circuit
- P0330 Knock sensor B circuit (bank 2)
- P0332 Knock sensor B circuit low (bank 2)
- P0316 Engine misfire detected on start-up (first 1,000 revolutions)
- P0315 Crankshaft position system variation not learned
Data: TORKO fault-code catalogue, built on OBDex (CC0-1.0) and reviewed against workshop practice. Informational only — it does not replace a diagnosis by a mechanic.
Updated: