P0321 — Ignition/Distributor Engine Speed Input Circuit Malfunction
Drive with caution — fix soon.
What P0321 means
This code means the engine computer detected a problem with the engine speed (RPM) input signal coming from the ignition or distributor circuit. It's commonly caused by a faulty crankshaft or distributor sensor, damaged wiring, loose connectors, or a failing distributor. Fixing it usually involves testing and replacing the sensor or repairing the wiring, and it's often resolved without major engine work.
Common symptoms
- Check engine light is on
- Engine stalls or shuts off unexpectedly
- Hard starting or no start
- Rough running or hesitation
- Inaccurate or erratic tachometer reading
Common causes
- Faulty crankshaft or distributor speed sensor
- Damaged or corroded wiring in the circuit
- Loose or dirty electrical connectors
- Failing distributor or pickup coil
- Problem with the engine control module
Typical repair cost
$150 – $700
Varies by vehicle and root cause.
Frequently asked questions
Can I keep driving with a P0321 code?
You can sometimes drive short term, but it's risky because the engine may stall or fail to restart. To avoid being stranded, limit your driving and get it diagnosed soon.
How much does it cost to fix a P0321 code?
Repairs usually range from $150 to $700. A sensor replacement is on the lower end, while wiring repairs or distributor work can cost more.
Is a P0321 code serious?
It's moderately serious. The car may still run, but the faulty speed signal can cause stalling or starting problems that leave you stranded, so it shouldn't be ignored.
What sensor usually triggers P0321?
It's most often the crankshaft position sensor or, on older vehicles, the distributor pickup that reports engine speed. Wiring and connector issues in that circuit are also common culprits worth checking.