What are the common causes of P0321?

A faulty crank or engine speed sensor. Wiring or connector faults on the sensor circuit. Incorrect sensor installation or gap. A damaged sensor tone ring. A faulty PCM input.

Read engine speed data on a scan tool. Inspect the sensor wiring and connector. Check the sensor installation and gap. Inspect the tone ring for damage. Replace the crank or engine speed sensor if it reads wrong. Clear the code and retest.

P0321

Ignition/Distributor Engine Speed Input Circuit Range/Performance

System: Ignition and misfire (P code)
Lamp: Check Engine Light
Category: Powertrain - Ignition

What it means

P0321 means Ignition/Distributor Engine Speed Input Circuit Range/Performance.

Check these first

A faulty crank or engine speed sensor
Wiring or connector faults on the sensor circuit
Incorrect sensor installation or gap
A damaged sensor tone ring
A faulty PCM input

What to do next

Read engine speed data on a scan tool
Inspect the sensor wiring and connector
Check the sensor installation and gap
Inspect the tone ring for damage
Replace the crank or engine speed sensor if it reads wrong
Clear the code and retest

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Updated

Generic SAE J2012 definition. Last updated 2026-10-10.