OBD-II code · Powertrain (generic)
P031A Ignition C Control Signal Circuit/Open
The ignition C control signal circuit is open — typically the PCM drive line for the first ignition coil group has lost continuity.
Is it safe to drive with P031A?
Usually safe to drive in the short term. Get it diagnosed when convenient, sooner if the car drives differently.
Common causes
- Most likelyOpen wire between PCM and coil
- Less likelyPin pushed back out of connector body
- Less likelyCracked solder joint inside the module or sensor
Repair at a glance
- Difficulty
- Medium
- DIY friendly
- Often, with basic tools
- Typical labour
- 0.5–2.5 h
- Emissions test
- Likely to fail
- Parts involved
- Ignition Coil
Related codes
- P030AIgnition A Control Signal Circuit/Open
- P030DIgnition B Control Signal Circuit/Open
- P031DIgnition D Control Signal Circuit/Open
- P035AIgnition E Control Signal Circuit/Open
- P035DIgnition F Control Signal Circuit/Open
- P036AIgnition G Control Signal Circuit/Open
- P036DIgnition H Control Signal Circuit/Open
- P038AIgnition I Control Signal Circuit/Open
- P038DIgnition J Control Signal Circuit/Open
- P03FAIgnition K Control Signal Circuit/Open
- P03FDIgnition L Control Signal Circuit/Open
- P0317Rough Road Hardware Not Present
- P0318Rough Road Sensor A Signal Circuit
- P0319Rough Road Sensor B Signal Circuit
- P031BIgnition C Control Signal Circuit Low
- P031CIgnition C Control Signal Circuit High
Code data: OBDex open dataset (CC0). Labour times are typical ranges, not a quote.