P0327 Knock Sensor 1 Circuit Low Input (Bank 1 or Single Sensor)

P0327 indicates a low input from knock sensor 1 on bank 1 or a single-sensor setup. The module sees a knock-sensor signal lower than expected.

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 tune around a knock-sensor low-input fault; the engine may lose important detonation protection while the code is active.

Symptoms of P0327

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 P0327

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

Inspect knock-sensor wiring, connector fit, shielding, sensor mounting, and harness routing around hot or hidden engine areas.
Check for water intrusion, corrosion, rodent damage, or harness repairs that can weaken the knock-sensor signal.
Review timing, fuel quality, and actual knock symptoms only after the sensor circuit has been proven reliable.

Related OBD-II codes

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