P0321 — Ignition/Distributor Engine Speed Input Circuit Range/Performance
Engine speed input from the ignition/distributor is in electrical range but plausibility check fails — slow response, drift, or noise.
General code reference. Confirm the definition and diagnostic procedure for your vehicle's year, model and engine. A stored code alone does not identify a failed part.
Affected components
- Ignition distributor
Possible causes to check
These are possible checks, not a ranked diagnosis. Follow the vehicle manufacturer's test procedure before replacing parts.
- Sensor drift or pickup gap wrong
- Sensor element aged beyond calibration window
- Sensor mounting loose - signal damping
Diagnostic notes
- The malfunction indicator lamp may illuminate
- This code can affect emissions
Related codes
Sources
Check each reference's vehicle and model-year scope. General background links do not establish which fault is most likely on your vehicle.
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.