P0325: the knock sensor circuit has a fault
The knock sensor listens for the faint pinging sound of fuel burning unevenly inside the cylinder, called knock, so the engine control unit can pull the ignition timing back before any damage is done. This code means the electrical circuit for bank 1's sensor, or the only sensor on a single-bank engine, isn't behaving the way the computer expects. Without a working knock signal the computer tends to play it safe and hold the timing back everywhere, not just where knock might happen.
You might notice
- The engine warning light comes on
- The engine may feel slightly less responsive, or use a little more fuel
- knock sensor
- — a sensor that listens for the sound of fuel burning unevenly, called knock
- ignition timing
- — exactly when the spark fires in the engine's cycle
What the code itself says
P0325 is a powertrain (engine, gearbox and drive system) code, and the 0 after the letter means it is a generic code with a standard meaning.
Grouped here as: Engine running, fuelling and misfires — Air metering, fuelling, ignition, misfire, idle, boost, knock, oxygen sensors and the catalyst, all working together in the running engine. That grouping is ours, to help explain the code. The code's official family is the letter at the start.
This page is generic. Your car isn't.
A code on its own only tells you what the sensor saw, not what's actually wrong — and that changes next to your other codes. Read this one together with the rest of your scan and we'll work out what's really going on.
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