Ignition & misfire · Powertrain · generic (SAE-defined)
P0356: Ignition Coil "F" Primary/Secondary Circuit
P0356 means ignition coil "F", commonly the cylinder 6 coil, has a primary or secondary circuit fault detected by the engine computer.
Standard title per SAE J2012 / ISO 15031-6 · Updated 2026-11-07 · By CarWhere Research
How P0356 sets
The powertrain control module (PCM) drives coil "F" and checks the circuit's electrical behavior. When it sees an open, short, or out-of-range feedback signal, it sets P0356. Coil letter assignments depend on the manufacturer.
Common causes of P0356
Roughly most likely first; the actual cause depends on the vehicle and needs testing to confirm.
- Failed ignition coil "F"
- Damaged coil wiring, often on a hard-to-reach rear bank
- Corroded or loose connector
- Worn spark plug
- Power or ground circuit fault
P0356 symptoms
- Check engine light on or flashing
- Misfire, often in cylinder 6
- Rough idle
- Hesitation
How P0356 is diagnosed
- Review freeze frame data and P0306 if present.
- Identify which cylinder coil "F" serves.
- Inspect coil, wiring, and connector.
- Swap coil "F" with another and retest.
- Check coil power, ground, and control circuits.
Typical fixes for P0356
- Replace ignition coil "F"
- Repair wiring or connector
- Replace spark plugs
- Restore coil power or ground
Replace parts only after testing confirms the cause — a code names the circuit or condition that failed a check, not necessarily the faulty part. We don’t publish per-repair prices; for what households actually spend on upkeep, see car repair costs.
Related codes & warning lights
P0356 FAQ
What does code P0356 mean?
P0356 means ignition coil "F", commonly the cylinder 6 coil, has a primary or secondary circuit fault detected by the engine computer. The standard definition is "Ignition Coil "F" Primary/Secondary Circuit."
Can I drive with a P0356 code?
Short, careful drives may be possible, but a misfire is likely. If the check engine light flashes, stop driving soon to protect the catalytic converter.
Why is coil F harder to replace on some engines?
On many transverse V6 engines, coil "F" sits on the rear bank under the intake plenum, which may need to be removed for access.
Can a bad coil cause poor fuel economy?
Yes. A misfiring cylinder wastes fuel and the engine works harder to maintain power, lowering mileage.
Can P0356 cause the engine to stall?
Losing one cylinder rarely stalls an engine by itself, but the rough running can make idle unstable. If stalling occurs, look for an additional cause such as a shared power or ground fault.
Keep researching
Engine guides by brand (known issues, specs)
More ignition & misfire codes
Sources
- SAE J2012 — Diagnostic Trouble Code Definitions (standard code titles)
- ISO 15031-6 — Road vehicles: communication between vehicle and external equipment for emissions-related diagnostics, Part 6: Diagnostic trouble code definitions
- U.S. EPA — Vehicle Emissions Inspection and Maintenance (I/M) programs
- U.S. EPA, 40 CFR 86.1806-17 — Federal onboard diagnostics requirements for light-duty vehicles
General information written by CarWhere Research, not a diagnosis of your vehicle. Manufacturers can add their own sub-definitions and test conditions; confirm with the factory service information for your year, make and model. Before paying for a repair, check NHTSA for open recalls and your warranty booklet: federal law requires an emissions warranty on major emission-control parts such as the catalytic converter and engine computer.