Code P0321, Ignition Control 24X Signal Circuit Error: Notes

The 24X Crankshaft Position (CKP) sensor is used to improve idle spark control at low speeds. Sensor is located behind harmonic balancer on front of engine and picks up pulses from reluctor wheel on crankshaft. Sensor signal is conditioned by PCM and used to more accurately control spark at lower engine speeds (less than 1200 RPM) where spark control is critical for idle quality.

Code P0321 will set when the following conditions are present.

• 150 or more 3X reference pulses seen without a 24X signal pulse received.
• Engine speed is less than 1200 RPM.
• Engine is running.
  NOTE: Test numbers refer to numbers on diagnostic chart.

1. Determines if signal voltage is present up to PCM.
2. Determines if 12 volts at sensor input.
3. By applying battery voltage to 24X crankshaft sensor circuit, harness and sensor integrity can be determined.
4. Checks ground path continuity.