Ignition and misfires code
P0356: Ignition coil F circuit problem
How this range is built
| Part of the job | Low | High |
|---|---|---|
| Parts | $30 | $120 |
| Labor: 0.4 to 1.2 hours × $125 to $175 an hour | $50 | $210 |
| Fees: shop supplies, disposal, diagnostics | $0 | $15 |
| Total, rounded | $80 | $350 |
The hourly rate is the BLS Occupational Employment and Wage Statistics, May 2025 average pay for this trade in Boston, $31.54 an hour, times 4 to 5.5 to cover what a shop bills (overhead, tools, insurance, profit). Parts are a band from budget aftermarket to the manufacturer part. Full method.
Not a repair shop, estimates only. Typical range, estimate. Not a quote. Your car, parts and shop change the number.
This is the range for the most common fix, ignition coil replacement (one coil). Which repair your car needs depends on a proper diagnosis.
The computer switches coil F on and off to fire a spark plug and checks the circuit. It found an electrical fault on coil F, the sixth coil in the maker's lettering, so that cylinder may fail to spark. The result is a rough idle or a miss when you press the pedal.
- Safe to drive?
- Short trips only
- Most common cause
- Failed ignition coil
Steady light: drive gently to a shop. Flashing light: stop.
What you may notice
- Rough idle
- Misfire
- Lower fuel economy
- Check-engine light
Common causes, most likely first
- Failed ignition coil
- Loose connector
- Worn spark plug
- Wiring fault
Check this first
Swap coil F with another coil on the same bank and clear the code. If the problem follows the coil, replace it. If it stays put, have the shop check the connector, the wire and the computer's driver circuit.
Other repairs that sometimes fix P0356
| Repair | Typical range, Boston |
|---|---|
| Spark plug replacement | $95 to $580 |
| Diagnostic scan (check engine light) | $60 to $290 |
Before you pay
- Ask the shop what test showed this part is the cause, not just that the code appeared.
- Ask for parts and labor listed separately, and for the hours.
- Ask for a written OK before any extra work. Massachusetts rules require written authorization before repairs.
Got a quote already? Check it against the range. Want to see if your car has a recall tied to this problem? Check recalls by VIN.
Need to read a code yourself? OBD-II scanners on eBay (affiliate link, disclosure).
P0356 questions
Is coil F cylinder 6?
Often, but check your engine's firing order. Some engines letter their coils in a different sequence, so a scan tool or a repair diagram confirms which cylinder coil F feeds on your car.
Do I replace all coils?
Only the failed one unless the others test bad. If the plugs are old, ask the shop whether replacing them at the same time makes sense, since access is often the same job.
Why do they fail?
Heat and old plugs are the usual causes. Coils sit close to a hot engine and vibrate for years, and a worn plug forces the coil to work harder until it gives out.
How much does it cost to fix P0356?
The most common fix, ignition coil replacement (one coil), has a typical range of $80 to $350 in Boston. It is an estimate built from parts prices and local labor wages, not a quote. Your car and shop change it.
Related codes
More ignition and misfires codes
Code meaning written in our own words. Some codes mean different things on different makes, so check your scan tool or manual. Not a repair shop, estimates only.