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 replacement coil that was faulty from new. Fix the root cause first, because a new coil fitted over a worn plug or into an oil-filled plug well fails the same way the old one did.

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.

P0351: Ignition Coil A Primary/Secondary Circuit Malfunction

Quick Answer

Not safe to drive

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.

Severity: Moderate · Ignition
Estimated repair cost: From €55 to €1800+, varies by vehicle

€55 or €1800, depending on your car.

Replace ignition coil #1 only€55–€210
ECU repair or replacement (rare)€500–€1800

A scan shows whether P0351 is really stored on your car, which codes sit next to it and how urgent each one is. You can do this parked, with the ignition on.

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Point your phone camera at the code. Setup takes about a minute.

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A scan needs a Bluetooth OBD2 adapter (Bluetooth LE on iPhone), about €25-60; the built-in demo runs without one. See which adapter to buy

What does P0351 mean?

P0351 is a ignition-related diagnostic trouble code classified as moderate severity.

What are the symptoms of P0351?

Rough idle with a clear cylinder 1 misfire you can feel through the steering wheel
Check engine light on, flashing when the misfire is active under load
Power loss and hesitation on acceleration, especially uphill
Fuel economy drop of roughly 10 to 20 percent
Raw fuel smell from the tailpipe after a few minutes of running
Longer cranking before the engine catches

What causes P0351?

Failed ignition coil #1 (internal winding open or shorted)
: high
Corroded or oil-contaminated coil connector on cylinder 1
: high
Cracked coil boot arcing to the head or plug well
: medium
Worn spark plug with excessive gap overstressing the coil
: medium
Chafed or broken wire between ECU and coil primary
: low
Failed ECU ignition driver transistor for cylinder 1
: low

Is it safe to drive with P0351?

No - address this immediately. You can limp home, but don't keep driving on it. A dead coil dumps raw fuel into the exhaust and cooks the catalytic converter fast. Replacement cats run €600 to €1500 on most cars.

How do you diagnose 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?

Repair	Parts Cost	Labor Cost	Total Estimate	DIY Difficulty
Replace ignition coil #1 only	€25–€120	€30–€90	€55–€210	Easy
Replace coil #1 plus spark plug on cylinder 1	€35–€150	€40–€110	€75–€260	Easy
Full coil set and spark plug set replacement	€120–€500	€80–€250	€200–€750	Moderate
Repair coil connector pigtail or harness section	€15–€80	€60–€200	€75–€280	Moderate
ECU repair or replacement (rare)	€400–€1500	€100–€300	€500–€1800	Professional

Prices estimated as of October 2026. Costs vary by region, vehicle, and shop.

Full repair guides

Ignition Coil Replacement Cost

P0351 on specific vehicles

Ford

Ford F-150

2004-2014

5.4L 3V Triton is prone to cracked coil boots and coils arcing to the head. Ford changed the coil version during production, so match the replacement to the one fitted to your truck.

Source: f150online.com

Volkswagen

VW Golf

2006-2016

The 1.4 TSI (EA111) and 2.0 TFSI (EA113/EA888) use coil-on-plug units, and several coil versions fit these engines, so check which one is on the car before ordering. On a high-mileage engine, replace the coils as a set of four.

P0351 on BMW

BMW 3-Series

See BMW-specific causes & cost

Toyota

Toyota Camry

2002-2011

2AZ-FE 2.4L coils are generally durable, and most failures happen at high mileage. Access is straight down through the valve cover, a short job.

Honda

Honda Civic

2006-2015

R18A1 1.8L often throws P0351 from a corroded connector rather than a bad coil. Check the coil connector and its pigtail before ordering parts.

Common questions about P0351

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 replacement coil that was faulty from new. Fix the root cause first, because a new coil fitted over a worn plug or into an oil-filled plug well fails the same way the old one did.
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.

Read our detailed guides

Sources

f150online.com f150online.com/forums/v8-engines/480174-dg511-new-style-dg521-coils-when-exactly

Before you pay up to €1800, check P0351 on your own car