P0325 Knock Sensor Circuit (Bank 1)
Get it checked soon
The knock sensor circuit is not working. The engine runs, but without its warning for knock, so the computer keeps timing on the safe side. Drivable; fix it soon and avoid heavy loads.
- Safe to drive?
- Yes, but avoid heavy loads
- Typical cost at a shop
- $417-$589 RepairPal national averages, parts and labor
- Emissions test
- Yes, while the check engine light is on, most OBD emissions tests fail the car.
- Carmaker bulletins
- 1 note with links
What it means
The knock sensor is a small microphone bolted to the engine block. It listens for the sharp ring of knock (detonation) so the computer can retard timing in time. P0325 means its circuit does not read right. The code does no harm by itself, but the engine has lost its early warning, and most computers respond by keeping timing retarded.
The technical version
The computer checks that the knock sensor signal stays in a plausible range for the engine speed. An open, short or missing signal sets P0325. P0326 to P0334 cover range and bank 2 versions. Some bulletins list P0325 with other knock codes from harness damage (see make notes).
Official name: Knock Sensor 1 Circuit Malfunction (Bank 1 or Single Sensor).
Symptoms
- Slightly less power and fuel economy.
- Often no other sign.
Causes, most likely first
| Cause | How likely | How to tell |
|---|---|---|
| A failed knock sensor | most common | Wiring is good but the signal is missing. |
| Corroded or damaged wiring or connector | common | Look where the harness runs near hot or sharp parts. |
| A sensor that is loose or over-tightened | less common | Recent engine work near the sensor. |
| Real, constant knock | rare | Audible pinging under load. |
How likely is our ranking from repair data and common practice, not a published rate.
What the live data shows
Timing advance shows it: many computers pull a few degrees and stay there once they stop trusting the knock sensor, so you see less advance under load than usual. Everything else usually looks normal. That quiet pattern is why this code gets ignored for too long.
What to check first, in order
-
Check the connector and wiring.
The cheap, common find.
What the data shows: No reading needed.
Cost: free to look
-
Check the make notes for a wiring bulletin.
Some engines have a known chafe point.
What the data shows: No reading needed.
Cost: free
-
Check the sensor's torque if it was disturbed.
Torque affects the reading.
What the data shows: No reading needed.
Cost: free
-
Replace the knock sensor.
Often cheap, but on some engines it sits under the intake manifold.
What the data shows: Timing advance returns to normal.
Cost: $417-$589 at a shop (Knock sensor replacement, RepairPal)
Is it safe to drive?
Get it checked soon
Yes, but avoid heavy loads. The engine has lost its knock protection.
Fine for normal driving. You will likely notice a small loss of power and economy. What you lost is protection: if the engine starts to knock from bad fuel, carbon or heat, the computer may not catch it. Skip towing, long mountain grades and low-octane fuel until it is fixed.
Stop driving and get help if
- You hear pinging or knocking under load.
What it costs
| Repair | Typical cost |
|---|---|
| Knock sensor replacementRepairPal, updated September 3, 2026 | $417-$589 |
National averages for the full job at a shop, parts and labor, from RepairPal (updated September 3, 2026). Your price depends on the car and the area. Many of the first checks on this page cost nothing with a scanner.
Can I clear it? Will it come back?
After the repair, clear the code and drive. Timing advance under load should return to normal.
Will it fail an emissions test?
Yes, while the check engine light is on, most OBD emissions tests fail the car.
Carmaker notes
Service bulletins and warranty extensions that name this code. Ask a dealer to check your VIN.
-
Ford 2016-2017 Explorer and Police Interceptor Utility 3.5L EcoBoost, built on or before September 30, 2016
Ford bulletin 18-2367 (December 2018) covers P0325, P0327, P0330 or P0332 from a wire chafe near the knock sensor connector.
Ford TSB 18-2367 via NHTSA static.nhtsa.gov
Related codes
Also related, no guide yet: P0327, P0332.
How Obie handles P0325
Obie reads timing advance under load and tells you whether the engine is running on safe timing because of the knock sensor. Obie is part of ScanMyCar Pro. Codes and live sensors are free.
Questions people ask
Can I drive with P0325?
Yes, normally. Avoid towing and heavy loads until it is fixed.
Does P0325 hurt the engine?
Not by itself. It removes the engine's knock protection, which matters if the engine starts to knock.
Is it always the sensor?
No. Check the wiring first; some engines have a known chafe point.
Sources
- RepairPal: P0325 code page repairpal.com
- RepairPal: Knock sensor replacement (updated September 3, 2026) repairpal.com
- Ford TSB 18-2367 via NHTSA static.nhtsa.gov
- Texas DPS emissions testing FAQ dps.texas.gov
- Arizona myazcar.com: OBD and the check engine light myazcar.com
A guide, not a diagnosis. This page describes what P0325 generally means across OBD2 cars. What is actually wrong with your car depends on its live data and its history, and any repair decision deserves a proper diagnosis, whether that is you with a scanner or a professional with a lift.
