P0325: Knock sensor 1 circuit fault (bank 1 or single sensor)

Knock sensor 1 circuit

Severity: Inspect soon

P0325 means the engine computer sees a fault in the knock sensor 1 circuit. The engine normally keeps running, but the computer may switch to a more conservative ignition strategy with less power and economy, and it may not be able to detect real knock. Get it inspected soon.

It gets more serious if:

Stop: You hear loud or persistent knocking or pinging from the engine, especially when accelerating. With a knock sensor fault the engine may not be able to detect and correct it, and repeated severe detonation can damage pistons and bearings. Avoid hard driving and get it checked before driving further.

Source: how we rate severity

P0325 in short

P0325 means the engine computer sees a fault in the circuit for knock sensor 1 (bank 1, or the only knock sensor). Wiring and connector problems are more common than a failed sensor. The engine usually runs, perhaps with less power, so get it inspected soon and stop if it knocks loudly.

A knock sensor is a small piezoelectric sensor bolted to the engine block. It produces a signal when it feels the vibration of knock (detonation), the uncontrolled burning that sounds like pinging. On the ASE reference design, the engine computer uses that signal to retard ignition timing when knock is detected.

P0325 sets when the circuit for knock sensor 1 (on bank 1, or the only sensor) reads open, shorted or out of range. When the computer cannot trust the sensor, it may run a more conservative ignition strategy, so performance and economy can drop even though the engine runs.

Wiring and connector faults are more common than failed sensors, and real knock from fuel or engine conditions can also be involved.

Most likely causes

These are general causes for this code across vehicles. None is specific to one make or model.

Cause 1: Damaged, loose or corroded knock sensor wiring or connector
Common general cause
Why it ranks here
Delphi notes engine vibration can shake a knock sensor connection loose, and wiring and connector faults are the first causes in independent guidance. Honda traced P0325 on some models to rodents chewing the knock sensor harness.
What would change this
Rises with visible damage, corrosion, chewed wires or a loose connector, or if the circuit reads open or shorted.
How to test the knock sensor
Cause 2: Failed knock sensor
Common general cause
Why it ranks here
The sensor itself can fail, but it is usually buried under the intake on V engines, so prove the wiring is good before replacing it.
What would change this
Rises if the wiring tests good but the sensor gives no signal when the block is tapped on a scope.
How to test the knock sensor
Cause 3: Knock sensor installed incorrectly (wrong torque or position)
Possible — needs testing
Why it ranks here
Knock sensors depend on firm contact with the block. Delphi and independent guidance name incorrect installation or mounting torque as a cause, especially after recent engine work.
What would change this
Rises if the code appeared after engine work or a sensor replacement; a shop checks torque and orientation.
How to test the knock sensor
Cause 4: Real engine knock (low-octane fuel, carbon buildup, overheating or a lean mixture)
Possible — needs testing
Why it ranks here
Real detonation from fuel below the octane the manufacturer calls for, carbon buildup, overheating or a lean mixture can be behind knock sensor codes.
What would change this
Rises if you hear pinging when accelerating, use lower-octane fuel than the owner's manual specifies, or also have lean or overheating codes.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Check the owner's manual for the required fuel octane and compare with what you use, then listen for pinging or knocking when accelerating moderately.
Low riskTool: owner's manual
- IfPinging is heard or the fuel is below the required octane
  It meansReal knock may be involved; fill with the correct fuel and avoid hard acceleration until checked.
  Points to: Real engine knock (low-octane fuel, carbon buildup, overheating or a lean mixture)
- IfNo pinging and the correct fuel
  It meansLook at the sensor wiring.
  Go to step 2
Step 2: With the engine off and cool, inspect the knock sensor harness and connector you can reach (often under or near the intake manifold) for chafing, corrosion, chewed wires or a loose connector.
Use cautionTool: flashlight, service information for the sensor location
Warning:Let the engine cool; parts near the sensor can burn. Do not remove the intake manifold yourself unless you have the service procedure and tools.
- IfDamage or a loose connector
  It meansRepair the wiring first.
  Points to: Damaged, loose or corroded knock sensor wiring or connector
- IfNothing visible
  It meansThe circuit and sensor need testing.
  Go to step 3
Step 3: Have a shop test the knock sensor circuit against the specification and view the sensor signal on an oscilloscope while tapping the engine near the sensor; they should also check the mounting torque.
Best left to a shopTool: lab scope, multimeter, service information
Warning:Access often requires removing intake parts. Leave it to a shop.
- IfCircuit open, shorted or out of range
  It meansWiring fault.
  Points to: Damaged, loose or corroded knock sensor wiring or connector
- IfCircuit good but no signal when tapped
  It meansThe sensor has failed.
  Points to: Failed knock sensor
- IfSensor loose, over-tightened or fitted wrongly
  It meansInstallation fault.
  Points to: Knock sensor installed incorrectly (wrong torque or position)

Symptoms

Reduced power or slower acceleration
Worse fuel economy
Pinging or knocking when accelerating Gets more serious: stop and have it checked.

Compare with: Check engine light with loss of power

How to fix

Step 1: Write down every stored code and the freeze-frame data before clearing anything, so you can tell whether the code comes back.
Step 2: Use at least the fuel octane listed in the owner's manual.

On your vehicle

Honda

2003–2004 · Accord
Supported by vehicle data
Honda traced P0325 on this model to rodent damage to the knock sensor harness. Check the harness before replacing the sensor.
1999–2004 · Odyssey
Supported by vehicle data
Honda traced P0325 on this model to rodent damage to the knock sensor harness. Check the harness before replacing the sensor.
2003–2004 · Pilot
Supported by vehicle data
Honda traced P0325 on this model to rodent damage to the knock sensor harness. Check the harness before replacing the sensor.

105Status unverified
Honda 105: P0325 from rodent damage to the knock sensor harness
1999–2004accord, odyssey, pilot · issued May 16, 2004 · NHTSA 10014120
P0325 traced to rodent damage to the knock sensor harness on 2003-2004 Accord, 1999-2004 Odyssey and 2003-2004 Pilot.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

Jeep

2020–2021 · Wrangler
Supported by vehicle data
FCA has a service communication for P0325 on this model. The summary does not give the repair, so ask a dealer to check it before replacing parts.

S2008000033Status unverified
FCA S2008000033: MIL with P0325
2020–2021wrangler · issued May 19, 2020 · NHTSA 10176538
Covers a check engine light with P0325 on 2020-2021 Wrangler. NHTSA's summary does not give the cause or repair.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

All Ignition and engine position sensors codes

P0325 questions

Can I keep driving with P0325?

Usually, for a short time and gently. Expect some loss of power and economy. Avoid hard acceleration and heavy loads, and stop driving and get it checked if you hear loud or persistent knocking or pinging.

Will premium fuel fix a knock sensor code?

Not a wiring or sensor fault. Using the octane your owner's manual specifies is still worth doing, because low-octane fuel can cause real knock, but the code will usually return until the circuit fault is repaired.

Why does the knock sensor matter if the engine runs fine?

It lets the engine computer detect knock and react to it. Without a trusted signal the computer may run a cautious strategy that costs power and economy, and it may not catch real knock that could damage the engine over time.

Sources and review

What Causes a Knock Sensor Code? 11 Common Causes — Rick's Free Auto Repair Advice (Rick Muscoplat) , July 27, 2022
ASE L1 Advanced Engine Performance Specialist Test: Composite Vehicle Type 4 Reference Booklet — National Institute for Automotive Service Excellence (ASE)
How to diagnose a faulty knock sensor — Delphi Technologies Aftermarket
GM 02-06-04-023: engine ping during acceleration and/or MIL with P0332 — General Motors (via NHTSA) , May 1, 2002
Honda 105: P0325 from rodent damage to the knock sensor harness — American Honda Motor Co. (via NHTSA) , May 16, 2004
Diagnostic Trouble Code (DTC) list — Delaware Division of Motor Vehicles
Hyundai Issues Recall and Engine Software Update for Certain Sonata and Santa Fe Sport Vehicles — Hyundai Motor America (press release via PR Newswire) , January 16, 2019
FCA S2008000033: MIL with P0325, Jeep Wrangler — FCA US LLC (via NHTSA) , May 19, 2020

Last reviewed: October 15, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Most likely causes

Cause 1: Damaged, loose or corroded knock sensor wiring or connector

Cause 2: Failed knock sensor

Cause 3: Knock sensor installed incorrectly (wrong torque or position)

Cause 4: Real engine knock (low-octane fuel, carbon buildup, overheating or a lean mixture)

What to test first

Step 1: Check the owner's manual for the required fuel octane and compare with what you use, then listen for pinging or knocking when accelerating moderately.

Step 2: With the engine off and cool, inspect the knock sensor harness and connector you can reach (often under or near the intake manifold) for chafing, corrosion, chewed wires or a loose connector.

Step 3: Have a shop test the knock sensor circuit against the specification and view the sensor signal on an oscilloscope while tapping the engine near the sensor; they should also check the mounting torque.