P031A

Ignition C Control Signal Circuit/Open

High severity

The ignition C control signal circuit is open — typically the PCM drive line for the first ignition coil group has lost continuity.

Common causes

Open wire between PCM and coil
One of the most commonly reported causes for this code — check this first.
high
Typical part cost: $70-550
Pin pushed back out of connector body
Less common, but worth ruling out after the more likely causes.
low
Typical part cost: $70-550
See all causes + fix costs
Create a free Wrenchify account to unlock the rest for P031A.
Unlock causes
Free forever · No credit card

First things to check

1Confirm the code with a scan tool and check for additional related codes.
2Inspect the relevant sensors, wiring, and connectors for damage or corrosion.

Get the full step-by-step diagnosis

Create a free Wrenchify account to unlock the rest for P031A.

Unlock diagnosis

Free forever · No credit card

Related codes

See related trouble codes

Create a free Wrenchify account to unlock the rest for P031A.

Unlock related codes

Free forever · No credit card

Frequently asked questions

What does P031A mean?

P031A means "Ignition C Control Signal Circuit/Open". It is a generic OBD-II code that points to a fault in the ignition system or misfire.

What are the most common causes of P031A?

open wire between pcm and coil; pin pushed back out of connector body; cracked solder joint inside the module or sensor — these are the most commonly reported causes. Verify with a proper diagnosis before replacing parts, or use the Wrenchify app for a vehicle-specific diagnosis.

Can I keep driving with this code?

This code points to a problem that can cause damage or affect safety. Avoid driving and have the vehicle diagnosed promptly. Use the Wrenchify app for a full diagnosis specific to your vehicle.

Get the full P031A diagnosis for your vehicle

Year, make, model + step-by-step repair help — free plan included.

Diagnose P031A