P038AIgnition I Control Signal Circuit/Open
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Can trigger limp mode
- How the car detects it
- Ignition I is one of the control signal lines from the engine module to an ignition module, ignition output stage or group of coils; which cylinders it serves is defined by the manufacturer, not by the code standard. The code concerns the logic-level control signal, not the coil's primary current (that has its own codes, P0351 ff and P2300 ff). P038A means the control line is open – the module sees a voltage with its driver off that indicates high resistance. No manufacturer using these codes was found – neither GM nor Ford use the Ignition A to J codes; GM reports coil control faults as P0351 ff – so the description follows CARB and that analogy. The affected coils fire wrongly or not at all, causing misfire; many modules then shut off injection to those cylinders to protect the catalyst.
- What you may notice
- Check engine light on
- Misfire, jerking, rough idle
- Loss of power, possibly cylinders shut off
- Additional misfire codes P0300 ff
- Likely causes
- LikelyControl line or connector pin open (corrosion, pushed-back pin)
- PossibleIgnition module or coil with integrated driver of this group faulty
- PossibleSupply or ground of the ignition module faulty
- RareDriver stage in the engine module
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €50 – €500
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.