What Does P0320 Mean?
The PCM has detected a malfunction in the ignition/distributor engine speed input circuit. This circuit provides the PCM with the engine RPM signal, which is critical for fuel injection timing, ignition timing, and transmission shift scheduling. The driver may experience a no-start condition, engine stalling, erratic RPM readings on the tachometer, or the engine cutting out unexpectedly while driving.
Safety Warning
This can cause sudden engine stalling while driving, which is a serious safety hazard, especially at highway speeds or in traffic. The vehicle may also fail to start. Do not drive the vehicle until this is repaired, as loss of engine speed signal can cause unpredictable stalling.
Common Causes
30%
Failed crankshaft position sensor (CKP) providing no signal to the PCM
25%
Damaged or corroded wiring between the CKP sensor and the PCM
20%
Faulty distributor pickup coil or cam/crank sensor in distributor-equipped engines
15%
Damaged crankshaft reluctor ring with missing or chipped teeth
10%
PCM internal failure in the engine speed input processing circuit
Diagnostic Steps
1
While cranking the engine, monitor the RPM PID on the scan tool — if the RPM reads zero or fluctuates wildly during cranking, the engine speed signal is not reaching the PCM.
2
Measure the CKP sensor resistance at the sensor connector (disconnect the PCM side): typical values are 500–900 ohms for magnetic-type sensors. Hall-effect sensors need a voltage check instead.
3
Use an oscilloscope to capture the CKP waveform during cranking — verify consistent amplitude (typically 0.5V+ AC for magnetic type) and look for missing or distorted pulses indicating a damaged reluctor.
4
Inspect the CKP sensor wiring for damage near the exhaust manifold, starter motor, and flexplate area where heat and vibration are extreme.
5
Check the sensor air gap to the reluctor wheel — excessive gap (over 1.5mm for most applications) causes weak signal strength. Remove and inspect the sensor tip for metallic debris.
Estimated Repair Cost
$100 - $500
Parts + labor, varies by vehicle and location
The PCM has detected a malfunction in the ignition/distributor engine speed input circuit. This circuit provides the PCM with the engine RPM signal, which is critical for fuel injection timing, ignition timing, and transmission shift scheduling. The driver may experience a no-start condition, engine...
The most common cause of P0320 (Ignition/Distributor Engine Speed Input Circuit Malfunction) is: Failed crankshaft position sensor (CKP) providing no signal to the PCM
Typical repair costs for P0320 range from $100 to $500, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This can cause sudden engine stalling while driving, which is a serious safety hazard, especially at highway speeds or in traffic. The vehicle may also fail to start. Do not drive the vehicle until this is repaired, as loss of engine speed signal can cause unpredictable stalling.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to P0320 to identify the root cause.
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Quick Info
Category
Powertrain
System
Ignition System / Engine Management
Difficulty
Type
Generic (SAE)
Recommended Tools
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