OBD Ignition K Control Signal Circuit/Open
What it means
P03FA stands for Ignition K Control Signal Circuit/Open. P03FA is a P code, so the fault sits in the engine, transmission and emissions systems. For P03FA, the second digit places it in ignition and misfire. For P03FA, work through the cause list below, cheapest checks first.
What to check first
For P03FA, check the wiring and connector on this circuit first, since a broken terminal gives the same reading as a failed part.
Check these first
- P03FA: Failing ignition coil, spark plug, or spark plug wire
- P03FA: Faulty crankshaft or camshaft position sensor
- P03FA: Wiring or connector damage in the ignition circuit
- P03FA: Low compression or engine mechanical wear
- P03FA: Incorrect ignition timing or a stretched timing chain
What to do next
P03FA reports from the ignition and misfire system. These steps cover P03FA in general, and the exact cause on your vehicle can differ from the cause named above.
- P03FA: Read misfire counts and freeze frame data with an OBD-II scanner
- P03FA: Test spark output and inspect spark plugs and coils
- P03FA: Check crankshaft and camshaft position sensor signals while cranking
- P03FA: Swap suspect ignition parts between cylinders to see if the fault moves
- P03FA: Compression test if the issue persists on the same cylinder
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Updated
Generic SAE J2012 definition. Last updated 2026-08-30.