P0351 means the ECU saw an electrical fault in the primary or secondary circuit of ignition coil #1. Usually a failed coil, sometimes wiring, connector, or the ECU's ignition driver.
DTC/P0351·Honda
P0351 on Honda: Causes, Symptoms and Fix Cost
Quick Answer
Moderate SeverityNot safe to driveHonda
P0351 on a Honda means the ECU saw an electrical fault in the primary or secondary circuit of ignition coil #1. Usually a failed coil, sometimes wiring, connector, or the ECU's ignition driver.
Repair cost on Honda€47 - €1530
What does P0351 mean on a Honda?
Honda Civic
2006-2015R18A1 1.8L often throws P0351 from a corroded connector rather than a bad coil. Check the pigtail (Honda 30520-RNA-A01 connector) before ordering parts.
What causes P0351 on a Honda?
Beyond the generic causes listed on the main P0351 page, these are the Honda-specific patterns we see most often:
Honda CivicGreen corrosion on the coil connector terminals from moisture wicking down the harness
Honda CivicCracked coil housing from repeated removal during 160,000 km plug changes
How to diagnose P0351 on a Honda with OBD2
Follow these steps to pinpoint the root cause of P0351:
- Scan for all stored codes. A P0301 alongside P0351 confirms cylinder 1 is the misfiring cylinder, not just an electrical hiccup.
- Pull the coil #1 connector and inspect for green corrosion, bent pins, or oil from a leaking valve cover gasket.
- Swap coil #1 with coil #3 (or any other cylinder), clear codes, and drive. If P0353 now appears, the coil is dead. If P0351 stays, the fault is wiring or ECU side.
- Pull spark plug #1. Check for excessive gap, oil fouling, or a cracked insulator. Replace it regardless while you're in there.
- Measure coil primary resistance (typically 0.4 to 2 ohms) and secondary (5k to 15k ohms). Compare to your service manual spec, not a generic number.
- Key on, engine off: confirm 12V at the coil power pin. Then back-probe the trigger wire and check for a switching signal while cranking.
- Trace the trigger wire back toward the ECU looking for chafe points, especially where the harness crosses the valve cover or a metal bracket.
- If coil, plug, power, and trigger wire all pass, scope the ECU driver output. A flat line while cranking points to a failed driver inside the ECU.
How much does P0351 cost to fix on a Honda? (EUR)
Estimated repair costs on a Honda (Honda parts and labour typically run 15% below the average for this code).
Prices estimated as of May 2026. Costs vary by region, vehicle, and shop.
Related codes that often appear with P0351 on Honda
These codes commonly cluster with P0351 on Honda vehicles:
FAQ: P0351 on Honda
Can I just swap coil 1 with coil 2 to test it?
Yes, that's the fastest way. Move coil 1 to another cylinder, clear the code, and drive. If P0352, P0353, or P0354 pops up, the coil is bad. If P0351 comes right back, look at the connector, wiring, or ECU driver.
Will P0351 wreck my catalytic converter?
Yes if you keep driving on it. Unburned fuel from the dead cylinder ignites in the cat and melts the substrate. A drive home is fine, a week of commuting on a flashing CEL usually isn't.
How long does it take to swap an ignition coil?
On most 4-cylinder coil-on-plug engines, 10 to 20 minutes. Two bolts and a connector. V6 or V8 engines with coils buried under an intake plenum (BMW N63, Audi 4.2 FSI) can take 1 to 3 hours.
My new coil failed within a month. Why?
Almost always one of three things: a worn spark plug you didn't replace, oil in the plug well from a leaking valve cover gasket shorting the boot, or a cheap aftermarket coil. Fix the root cause, use OEM (Bosch, Denso, Delphi, NGK), and it'll last.
Should I replace all the coils at once?
Not required, but if the car has 150,000+ km on original coils and one just died, the rest are close behind. On engines where labor is significant (BMW N54, VW/Audi TSI), replacing the set once is cheaper than four separate visits.
Looking for the full P0351 reference (all makes, full diagnosis flow, complete repair cost matrix)?
See the main P0351 guideSkanyx · Honda
Diagnosing P0351 on your Honda?
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