Ignition/Distributor Engine Speed Input Circuit Intermittent
P0323 indicates the PCM is not receiving a valid signal from the crankshaft position sensor (engine speed input circuit). Without this critical signal, the engine cannot determine ignition timing or fuel injection, causing it to either fail to start or run erratically. This code typically results from an open circuit, short circuit, or failed sensor in the CKP circuit.
What You Might Notice
- Engine cranks but will not start
- Malfunction Indicator Light illuminated
- Engine misfire, hesitation, or stumbling
- Lack of engine power or stalling
- Vehicle may die while driving
Most Common Causes
- 1
Faulty Crankshaft Position Sensor
The CKP sensor has failed or is producing an out-of-range signal. This is the most common cause as the sensor degrades over time due to heat and vibration exposure.
- 2
Open Ground Circuit
A break or poor connection in the ground circuit between the CKP sensor and PCM prevents signal completion. Check wiring harness and connectors for corrosion or damage.
- 3
Open Power Supply Circuit
The power supply wire to the CKP sensor is broken or disconnected, preventing the sensor from operating. Inspect the entire wiring harness from the PCM to the sensor.
- 4
PCM Failure
The engine control module itself has failed or the CKP input circuit within the PCM is damaged. This is less common but possible after confirming all wiring and sensors are functional.
How to Diagnose It
- 1
Check Faulty Crankshaft Position Sensor — The CKP sensor has failed or is producing an out-of-range signal. This is the most common cause as the sensor degrades over time due to heat and vibration exposure.
- 2
Check Open Ground Circuit — A break or poor connection in the ground circuit between the CKP sensor and PCM prevents signal completion. Check wiring harness and connectors for corrosion or damage.
- 3
Check Open Power Supply Circuit — The power supply wire to the CKP sensor is broken or disconnected, preventing the sensor from operating. Inspect the entire wiring harness from the PCM to the sensor.
- 4
Check PCM Failure — The engine control module itself has failed or the CKP input circuit within the PCM is damaged. This is less common but possible after confirming all wiring and sensors are functional.
How to Fix It
- 1
Replace Crankshaft Position Sensor
Remove the faulty CKP sensor from the engine block or crankshaft and install a new OEM or quality replacement. Reconnect the sensor harness and clear the code to verify the fix.
- 2
Repair CKP Sensor Wiring Harness
Inspect the wiring between the sensor and PCM for breaks, fraying, or corrosion. Replace damaged sections of the harness or repair connections with proper crimping and sealing techniques.
- 3
Clean or Replace CKP Connectors
Remove corrosion and oxidation from the CKP sensor connector pins using electrical cleaner and a soft brush. If connectors are damaged or heavily corroded, replace them with OEM connectors and reseal.
- 4
Test and Replace PCM if Necessary
After confirming the sensor, wiring, and connectors are functional, have the PCM tested by a qualified technician. If the CKP input circuit is faulty, the PCM may require replacement or reprogramming.
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