P0323 Ignition/Distributor Engine Speed Input Circuit Intermittent

P0323 points to an intermittent ignition or distributor engine speed input circuit. The controller sees the RPM reference drop out or become unstable unexpectedly.

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 call P0323 fixed after a static resistance test if the symptom only happens hot, wet, or under vibration.

Symptoms of P0323

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 P0323

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

Review freeze-frame RPM, stall history, tachometer dropouts, crank or distributor signal data, and related cam or ignition module codes.
Wiggle-test the harness and inspect connectors, terminals, heat-damaged wiring, sensor mounting, shielding, and grounds under the conditions that trigger the code.
Use scope capture or scan data recording during heat, vibration, and road-load testing to catch brief signal loss.

Related OBD-II codes

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