P0325: Knock Sensor Circuit Malfunction (Bank 1)
Your knock sensor isn't working properly. This sensor listens for the 'pinging' sound of engine knock (detonation) and tells the computer to retard ignition timing to prevent damage. Without it, the ECU can't protect your engine from knock.
Symptoms
- Check engine light
- Reduced power and acceleration
- Poor fuel economy
- Engine may ping on acceleration
Causes (Ranked by Likelihood)
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DIY Fix Steps
⚠ Safety first: work on a cold engine, chock wheels, use jack stands - never rely on a floor jack alone.
Usually on the engine block under the intake manifold. On most V6/V8 engines this requires intake manifold removal. On 4-cylinders it may be accessible from below.
Inspect the connector and wiring harness for corrosion, pinching, or damage. Clean corroded terminals with electrical contact cleaner. A wiring fix costs nothing.
A loose knock sensor gives false readings. Torque spec is usually 14-18 ft-lbs. Over-tightening also kills sensitivity. Use torque wrench.
On most vehicles, knock sensor is under the intake manifold. Budget 2-4 hours for manifold removal/reinstall. The sensor itself is $20-80.