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P0325

Knock Sensor 1 Circuit Malfunction

The car's computer is not getting the correct signal from the knock sensor. This sensor helps protect the engine from spark knock by telling the computer when the engine is vibrating abnormally. The problem may be the sensor, its wiring, or a connection issue.

Severity3/5 Moderate
Can I drive?⚠ With caution

You may be able to drive short distances, but engine protection may be reduced. If the engine runs rough, lacks power, or pings under load, diagnose it soon to avoid possible engine damage.

DIY
$20–$120
Shop
$120–$500
Difficulty
intermediate

What It Means

P0325 means the powertrain control module has detected an electrical fault in the knock sensor 1 circuit, usually on bank 1 or on engines with a single knock sensor. The fault can be an open circuit, short circuit, poor connector contact, damaged wiring, or a failed sensor. On some vehicles, related engine damage or unusually noisy engine operation can also affect the signal.

Symptoms

Common Causes

1. Failed knock sensorhigh
2. Damaged, corroded, or loose knock sensor connectorhigh
3. Broken, rubbed-through, or shorted wiring in the knock sensor circuithigh
4. Faulty engine control module input or internal module issuemedium
5. Incorrect sensor installed or wrong part numbermedium
6. Excessive engine noise from detonation, loose components, or internal engine problemsmedium
7. Water, oil, or coolant contamination in the connector or harnesslow

Related Codes

FAQ

Can a bad knock sensor cause loss of power?

Yes. Many vehicles reduce timing when the knock sensor signal is faulty, which can lower power and fuel economy.

Is P0325 always a bad sensor?

No. Wiring and connector problems are very common, and the code can also be caused by engine noise or a PCM issue.

Will clearing the code fix it?

No. The code will return if the circuit fault is still present.

Can bad fuel trigger P0325?

Bad or low-octane fuel can cause real engine knock, but P0325 usually points to an electrical circuit problem rather than fuel quality alone.