OBD
P031D
Ignition D Control Signal Circuit/Open
What it means
P031D stands for Ignition D Control Signal Circuit/Open. P031D is a P code, so the fault sits in the engine, transmission and emissions systems. For P031D, the second digit places it in ignition and misfire. For P031D, work through the cause list below, cheapest checks first.
What to check first
For P031D, check the wiring and connector on this circuit first, since a broken terminal gives the same reading as a failed part.
Check these first
- P031D: Failing ignition coil, spark plug, or spark plug wire
- P031D: Faulty crankshaft or camshaft position sensor
- P031D: Wiring or connector damage in the ignition circuit
- P031D: Low compression or engine mechanical wear
- P031D: Incorrect ignition timing or a stretched timing chain
What to do next
P031D belongs to the ignition and misfire system. These are the general steps for P031D, and the exact cause on your vehicle can differ.
- P031D: Read misfire counts and freeze frame data with an OBD-II scanner
- P031D: Test spark output and inspect spark plugs and coils
- P031D: Check crankshaft and camshaft position sensor signals while cranking
- P031D: Swap suspect ignition parts between cylinders to see if the fault moves
- P031D: Compression test if the issue persists on the same cylinder
Look up another code
Enter a full code or a symptom. Press / to search. How to read a code
Type a code above, or start from a symptom or a common code.
Updated
Generic SAE J2012 definition. Last updated 2026-08-30.