P0320
Ignition/Distributor Engine Speed Input Circuit
Encountering the engine check light code P0320 signifies an explicit mechanical or electrical operational breakdown categorized as "Ignition/Distributor Engine Speed Input Circuit". Professional scanner tools usually flag this subsystem loop early on.
Driver's Summary
The diagnostic trouble code P0320 indicates an active fault in the ignition/distributor engine speed input circuit circuit or component. Drivers typically experience engine stalling, tachometer drops to zero, hard start when this code is active. This condition is classified as high severity. Prompt diagnosis is essential to prevent cascading damage to related components.
Symptoms
Engine stalling, tachometer drops to zero, hard start
Common Causes
- Faulty crankshaft position sensor
- Failing ignition distributor
- Broken wire in speed input circuit
- Corroded electrical connection
How to Fix
- 1 Replace crankshaft position sensor
- 2 Replace or rebuild distributor
- 3 Repair broken wiring
- 4 Clean and secure sensor connector
Technical Explanation
Detection of P0320 occurs when the ECM cross-references multiple sensor inputs and determines that the reported values are physically inconsistent or out-of-range. Misfire rate is counted per cylinder over rolling windows and compared against two thresholds: a catalyst-damaging rate (triggers flashing MIL) and an emissions-exceeding rate (triggers solid MIL). The PCM logs which cylinder is misfiring based on crankshaft position at the time of each detected event. The MIL illuminates after the fault is confirmed on two consecutive drive cycles, and the freeze frame data captured at first detection is stored in the PCM's memory for diagnostic reference.
Is It Safe to Drive?
With P0320 active, your engine or transmission is not operating within design parameters. Short-term driving may seem fine, but internal damage is accumulating — particularly to faulty crankshaft position sensor.
Mechanic's Pro Tip
The most common mistake with P0320 is replacing the sensor without verifying the reference voltage and ground integrity first. Use a scan tool to monitor the sensor's live output; a truly failed sensor shows a stuck, flatlined reading — a sensor that fluctuates but reads slightly off usually indicates a wiring or vacuum issue, not a dead sensor. Always spray electrical contact cleaner on the connector pins before condemning the sensor.
Crank sensor: $100 - $250; Distributor: $200 - $450