P0325: Knock/Combustion Vibration Sensor A Circuit
A generic powertrain (engine and transmission) trouble code, same meaning on every brand.
Yes - the computer retards timing conservatively, trading a little power and economy for safety.
Symptoms
- Slight power and economy loss
- Possible pinging on hard acceleration in hot weather
Likely causes, most common first
- Knock sensor aged or unplugged
- Wiring damage - these sensors live low on the block
- Over-torqued or corroded sensor mount skewing the signal
Read P0325 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
P0325 means the knock sensor circuit is not delivering a usable signal. The sensor is a microphone tuned to detonation frequencies; deprived of it, the computer assumes the worst and pulls ignition timing back.
On V engines the sensors often hide under the intake manifold, which is why labor dominates the repair price. Use premium fuel as a stopgap if the engine pings before the fix - detonation is the damage this system exists to prevent.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning P0325
“- started shutting shutting off at while in drive. - started having reduced power - started idiling high while driving - initially there was no codes - last night I drove, I put in drive gear but it was delayed so I had to keep moving from park to drive for it to full go into drive - the codes came P0325 P0505 P0507 P0700 P1101 P2714 After I was driving up an incline the car stopped moving forward and started reversing backwards. One other independent shop advised they were able to produce but couldn't figure out the problem because no code were shown at the time. There has been many people having the same issues I started off with and I found the forum to file a report .”2019 Chevrolet Malibu · Nov 2025
“P0325 knock sensor multiple occurrences of sluggish performance causing safety risk when entering into traffic. This is the 3rd time I've replaced this sensor. And it's very dangerous when it happens. This happens at the exact same time last year at the end of June beginning of July 2024 as well which made Chicago driving very dangerous.”2018 Chevrolet Cruze · Jun 2025
“Faulty knock sensor at 83k miles. First symptoms were slow/jerky acceleration and needing to apply more pressure to the gas pedal to maintain speed, followed by illuminated Check engine light that came on a few days later. The scanner at Autozone pulled the code P0325. Improper detonation regulation is dangerous. This vehicle has been well maintained but needed all four pistons replaced after 60k miles and the cause of the piston damage is unknown. In this vehicle's history is also intermittent stalling and the vehicle turning completely off after idling, but dealership could not reproduce either issue. Those problems appeared early in the vehicle's life/well within warranty.”2017 Chevrolet Cruze · Jun 2022
Show 3 more owner reports
“I bought my 2010 GMC Terrain SLE at 160,000. It had a rough start up but the dealer said it was because it was an older car and been sitting for a while. The rough start up never stopped even after replacing the catalytic converter because of code P0420. The mechanic informed of this specific vehicle oil composition so I was consistently checking the oil. A month after the NEW catalytic converter was installed. I stalled out on the interstate with traffic going 65 mph minimum, the wheel locked and I was almost rear ended. I take the vehicle to an automotive shop and I need a new timing chain with numerous new codes. P0325 P0326 P0327 P0016 P0017 P0014.”2010 GMC Terrain · Nov 2021
“The car is a 2014 chevrolet cruze lt that was just purchased from a used car dealer and within the first week the engine retards itself and throws a check engine light. The code reads p0325 when read. The wiring has been checked out and has nothing wrong. The knock sensor has been replaced twice. After being replaced, the code will go away anywhere from a few minutes to a month and then the same issue starts all over again.”2014 Chevrolet Cruze · Nov 2020 · 94,000 mi
“This is the fourth time in 3 years that the same warning light has come on and at least the second time I've been told I have "spider webs in my cannister". ( I drive my car daily---don't see that happening). The computer codes, this time around, are: p1446 and p0325. Diagnosis: "needs vent control valve and cannister" " found spider webs in cannister and might need new one in future." I've no idea what any of this means, but the same warning light with an easy fix (they said they wiped out the webs) indicates that somethins is wrong with the system.”1999 Nissan Quest
Cars that report P0325 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with P0325?
Yes - the computer retards timing conservatively, trading a little power and economy for safety.
How much does it cost to fix P0325?
Typical US repair costs range from $80 for the simplest fix (wiring or connector repair) to $700 in the worst case. The right number depends on which cause your car has - see the causes list.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.