P0325
Knock Sensor 1 Circuit (Bank 1)
Quick answer: P0325 means knock Sensor 1 Circuit (Bank 1). Fixing the underlying cause typically runs $260 to $780 at an independent shop. Drive gently, service soon.
- Severity
- Moderate
- Safe to drive?
- Drive gently, service soon
- Typical repair
- $260 to $780
- Most likely cause
- A failed knock sensor (the most common cause, and these do wear out with age and heat cycles)
What P0325 means
The knock sensor is a small microphone bolted to the engine that listens for the pinging of detonation (also called spark knock), which can damage pistons over time. When it hears knock, the computer retards timing to stop it. P0325 means the sensor's circuit on bank 1 has gone open, shorted, or out of range, so the computer can no longer trust it to hear knock. As a safe default it often runs more conservative timing, which is why the car feels a little softer and drinks a bit more fuel.
Common symptoms
What drivers usually notice with this code.
- Check-engine light, frequently with no dramatic drivability change
- Slightly reduced power and throttle response, since the computer defaults to safe, retarded timing
- A small drop in fuel economy
- Occasional pinging or knocking under load if timing is not being pulled correctly
- Sometimes mild hesitation on acceleration
Common causes
Ranked from most to least likely.
- 1A failed knock sensor (the most common cause, and these do wear out with age and heat cycles)
- 2A corroded, loose, or damaged knock sensor connector
- 3Broken or chafed wiring in the sensor circuit, sometimes from heat near the engine
- 4A loose knock sensor mounting bolt, which changes how it reads vibration and can trip the code
- 5Moisture or corrosion where the harness meets the sensor, common on higher-mileage engines
- 6A wiring or driver fault in the engine control module, which is rare
Can I keep driving?
Yes, you can usually drive with this, but the engine may pull back ignition timing to protect itself, so expect slightly reduced power and worse fuel economy until it is fixed.
Severity: Moderate. A flashing check-engine light always means stop, whatever the code says.
Ballpark cost
What P0325 usually costs to fix
A range, not a quote. What you pay depends on your vehicle, your area, and which of the causes above turns out to be the real one.
Typical parts and labor at an independent shop. Dealer rates run higher.
That spread is wide on purpose. P0325 points at a system, not a single part, so the real answer depends on what the diagnosis finds. Use the range to know what to expect. If an estimate comes in higher, it usually means the specific repair is more involved, and it is always fair to ask what is included.
Next steps
What to do next
The part itself is often inexpensive, so ask where your knock sensor actually sits before you accept a quote: on many V6 and V8 engines it is buried under the intake manifold, and the labor to pull the intake to reach it is what drives the price, not the sensor. Have the shop check the connector and wiring first, since a corroded plug or loose mounting bolt can throw this code without a bad sensor. If the intake does have to come off, ask whether it makes sense to replace both knock sensors and refresh the intake gaskets while it is open, so you are not paying that same labor twice a year later.
Walk in informed
Ask for the diagnosis in writing and which test confirmed it, so you understand exactly what is being fixed. Fixxr shows you what the job typically costs near you, so you can approve the work with confidence.
Sources & further reading
- NHTSA — Check for vehicle safety recalls — look up open recalls for your vehicle by VIN, free
- FTC — Auto repair basics — your consumer rights at the repair shop
- AAA — Car repair and maintenance costs — independent guidance on what repairs should cost
Cost ranges and guidance reviewed July 2026.
P0325 FAQ
P0325 questions, answered
Can I drive with a P0325 code?
Yes, you can usually drive with this, but the engine may pull back ignition timing to protect itself, so expect slightly reduced power and worse fuel economy until it is fixed.What does the P0325 code mean?
The knock sensor is a small microphone bolted to the engine that listens for the pinging of detonation (also called spark knock), which can damage pistons over time. When it hears knock, the computer retards timing to stop it. P0325 means the sensor's circuit on bank 1 has gone open, shorted, or out of range, so the computer can no longer trust it to hear knock. As a safe default it often runs more conservative timing, which is why the car feels a little softer and drinks a bit more fuel.What are the most common causes of a P0325 code?
The most likely causes, roughly in order, are a failed knock sensor (the most common cause, and these do wear out with age and heat cycles); a corroded, loose, or damaged knock sensor connector; broken or chafed wiring in the sensor circuit, sometimes from heat near the engine; a loose knock sensor mounting bolt, which changes how it reads vibration and can trip the code. The part itself is often inexpensive, so ask where your knock sensor actually sits before you accept a quote: on many V6 and V8 engines it is buried under the intake manifold, and the labor to pull the intake to reach it is what drives the price, not the sensor. Have the shop check the connector and wiring first, since a corroded plug or loose mounting bolt can throw this code without a bad sensor. If the intake does have to come off, ask whether it makes sense to replace both knock sensors and refresh the intake gaskets while it is open, so you are not paying that same labor twice a year later.How much does it cost to fix a P0325 code?
Fixing the underlying problem behind a P0325 code typically runs $260 to $780 at an independent shop, including parts and labor. The exact figure depends on your vehicle and which part turns out to be at fault.
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