P031B
Ignition C Control Signal Circuit Low
Generic OBD-II
Common symptoms
What you'll notice
- Check for loose or damaged ignition control module connections.
- Inspect and replace ignition control module if necessary.
- Test and replace ignition coil, if found to be faulty.
- Check and replace spark plugs, if worn out or damaged.
- Verify and repair any wiring issues in the ignition control signal circuit.
Common causes
Most likely first
- Malfunctioning ignition control module or ignition coil
- Faulty ignition switch or key cylinder
- Defective ignition control unit or PCM
- Loose or damaged wiring in the ignition control circuit
- Faulty engine control module (ECM)
How to diagnose & fix
Work through it in order
- Engine misfire or rough idle
- Difficulty starting the vehicle
- Decreased fuel efficiency
- Engine stalls or shuts off while driving
- Increased emissions levels
Read & clear P031B yourself
Scan your car, confirm the code, and clear it once it's fixed — with OBD DashX on your phone.