P0326 Knock Sensor 1 Circuit Range/Performance (Bank 1 or Single Sensor)

P0326 points to a range or performance issue in Knock Sensor 1 circuit on Bank 1 or on a single-sensor engine. The knock signal is present but not believable for current conditions.

Code details

Generic OBD-II · P0

System: Ignition / Misfire
Code type: Generic (SAE / ISO controlled)
Standard: SAE J2012 / ISO 15031-6

Diagnostic boundary

A diagnostic trouble code reports that a monitored test failed. It does not prove one specific part is bad, and manufacturer logic can add vehicle-specific conditions.

Do not assume P0326 always means a bad knock sensor; mounting, wiring, fuel, and mechanical noise can all distort the signal.

Symptoms of P0326

Rough idle, shaking, or a stumble under acceleration.
A flashing check-engine light during an active misfire.
Power loss and higher fuel consumption.

Common causes of P0326

Worn spark plugs, ignition coils, or plug wires.
Fuel-delivery problems — injectors, pressure, or a lean/rich mixture.
Vacuum leaks, low compression, or a mechanical fault in that cylinder.

Useful checks before replacing parts

Compare Knock Sensor 1 signal, ignition timing correction, engine load, fuel octane, coolant temperature, and freeze-frame conditions.
Inspect sensor torque, mounting surface, harness routing, connector corrosion, shielding, engine mechanical noise, and nearby components contacting the block.
Check for a signal that is too flat, too noisy, or inconsistent with actual engine noise before replacing the sensor.

Related OBD-II codes

These nearby ignition / misfire entries can help compare wording and pin down the fault area.