Ignition and misfires code
P0351: Ignition coil A 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 sends a signal to switch coil A on and off to fire a spark plug, and it checks the circuit for a proper response. This time it saw an electrical fault. Coil A is the first coil in the engine's firing arrangement, so the matching cylinder may not spark correctly.
- Safe to drive?
- Short trips only
- Most common cause
- Failed ignition coil (most common)
If the check-engine light is steady you can drive gently to a shop. If it flashes, pull over and stop, because raw fuel can damage the catalytic converter.
What you may notice
- Rough idle
- Hesitation or shaking when accelerating
- Poor fuel economy
- Check-engine light, maybe flashing
Common causes, most likely first
- Failed ignition coil (most common)
- Loose or damaged coil connector
- Worn spark plug stressing the coil
- Wiring fault between the coil and the computer
Check this first
Swap coil A with a neighbor coil. If the code follows the coil, you have found the bad part. Also check that the connector is clipped on fully.
Other repairs that sometimes fix P0351
| 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).
P0351 questions
Should I replace all coils at once?
Not always. On a high-mileage car many shops replace the failed one and offer plugs at the same time, since worn plugs stress coils. Ask what the other coils test like before you pay for the whole set.
Is P0351 the same as a misfire?
They are related. P0351 points to the coil's electrical circuit, and a misfire code for that cylinder often appears alongside it. Fixing the coil or wiring normally clears both.
Can I clear the code and keep going?
It will probably return. Repeated misfires send raw fuel to the catalytic converter and can damage it, which costs far more than a coil. It is better to fix the cause than to keep clearing the light.
How much does it cost to fix P0351?
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
- P0352: Ignition coil B circuit problem
- P0300: Random or multiple cylinder misfires
- P0301: Cylinder 1 misfire
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.