OBD codes / P0325
P0325
ModerateKnock Sensor 1 Circuit Malfunction (Bank 1)
P0325 is generally safe to drive with — the computer protects the engine by running conservative timing when it can't hear the knock sensor. You may notice slightly less power and economy. Fix it at your convenience, but sooner if you hear pinging under acceleration.
What this code means
The knock sensor "listens" for the rattle of detonation (pinging) and lets the computer pull ignition timing to protect the engine. P0325 means the knock sensor circuit isn't reading correctly. Usually it's a failed sensor or a wiring/connector problem (corrosion is common because the sensor sits in a harsh spot). With no usable knock signal, the computer runs conservative timing as a safeguard, which costs a little power and fuel economy but keeps the engine safe.
Symptoms you might notice
- Check-engine light, often with no obvious change
- Slight loss of power or acceleration
- Minor drop in fuel economy
- Occasional pinging under load if timing isn't protected
What it costs to fix
Typical range: $150–$600 · about ~0.5–3 hrs of labor
| If the cause is… | Part | Labor |
|---|---|---|
| Knock sensor | $30–$200 | ~0.5–3 hrs |
| Wiring / connector repair | $10–$120 | ~0.5–1.5 hrs |
The sensor itself is inexpensive, but on many V6/V8 engines it sits under the intake manifold, so labor to reach it can be the bulk of the bill. On engines where it's easy to access, this is a cheap repair.
The price swings on which cause it turns out to be — so confirm the cause before paying. Diagnose P0325 for my exact vehicle →
Frequently asked
Can I drive with P0325?
Yes, generally — without a knock signal the computer plays it safe with timing, so the engine is protected, just slightly less peppy and efficient. If you hear pinging under load, get it addressed sooner.
What does the knock sensor do?
It detects the vibration of detonation (pinging) and signals the computer to retard ignition timing to stop it. It's a protective sensor — losing it doesn't damage the engine by itself, but it removes that safeguard.
Why is P0325 sometimes expensive to fix?
The sensor is cheap, but on many V6 and V8 engines it's mounted in the valley under the intake manifold. Getting to it means removing the intake, which is most of the labor and cost. On easy-access engines it's a quick, inexpensive job.
How much does it cost to fix P0325?
It ranges widely by engine — cheap where the sensor is accessible, several hundred where the intake has to come off. A wiring or corrosion fix is inexpensive. Check the connector before condemning the sensor.
Seeing P0325 on your car? Get a diagnosis specific to your exact year, make and model.
Diagnose P0325 for my vehicleGeneric OBD-II reference. Manufacturer-specific behavior varies — confirm with a scan tool and, for safety-related codes, a professional inspection.