Ignition/Distributor Engine Speed Input Circuit Intermittent
What does P0323 mean?
The P0323 code means the vehicle's onboard diagnostic system has detected: Ignition/Distributor Engine Speed Input Circuit Intermittent. This is a moderate severity code.
Common Symptoms
- Intermittent engine stalling
- Engine stumbles or hesitates randomly
- Check Engine Light comes on and off
- Tachometer drops to zero momentarily
- Occasional hard starting
Probable Causes (Ranked by Likelihood)
- Loose or corroded CKP sensor connector Very High
- Intermittent break in sensor wiring High
- CKP sensor failing under heat High
- Loose sensor mounting allowing vibration-induced signal loss Moderate
- Intermittent PCM input circuit fault Low
Step-by-Step Diagnostic Procedure
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Wiggle-test the CKP sensor connector and wiring while monitoring RPM on a scan tool
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Test the sensor resistance when cold and again after the engine reaches operating temperature -- a large change indicates heat failure
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Check the sensor mounting bolt for proper torque -- a loose sensor can vibrate and lose signal
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Monitor the CKP waveform with an oscilloscope during a road test to capture intermittent dropouts
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Inspect wiring harness for chafing, especially where it routes near moving parts or hot exhaust components
Frequently Asked Questions
Can I drive with code P0323?
You can drive short distances, but be aware the engine may stall unpredictably. Avoid highway driving until the intermittent fault is resolved.
Why does my engine stall only when hot?
CKP sensors commonly fail when hot due to internal component breakdown from heat cycling. The sensor works fine when cold but loses signal as temperature increases. Replacing the sensor resolves this.
Can vibration cause an intermittent CKP signal?
Yes. If the sensor mounting bolt is loose or the connector is not fully seated, engine vibration can cause momentary signal loss. Always check physical connections first.