Ignition and pre-heatingGeneric OBD-II codeUrgency: Garage soon
Code P0351: ignition coil "A": circuit fault
What code P0351 means
The ECU detects a fault in ignition coil "A", which normally corresponds to cylinder 1: the primary circuit (the one that powers and triggers it) or the secondary (the spark) is not working as it should.[1][2]
On a Toyota V6 engine described by AutoDTCs, the ECU sends the firing command to the coil and expects a confirmation signal; if it does not receive it, it stores P0351 and turns the warning light on immediately. Each manufacturer uses its own criteria, so the exact procedure varies.[2][3]
It is a generic code (P0), with the same definition on all brands. Codes P0352 onwards are the same thing for coils "B", "C" and so on, that is, other cylinders.[1][4]
Original definition (SAE J2012): Ignition Coil "A" Primary/Secondary Circuit[1][2]
Codes from the same family
They indicate the same problem in a specific cylinder, bank or sensor. Causes, symptoms and diagnosis are those on this page.
Causes of P0351 and its family
From most to least likely, according to the sources.
- 1Faulty coil, with an open or shorted primary winding: the most common cause on engines with one coil per cylinder.[1][2]
- 2Worn or dirty spark plug, which demands more voltage and ends up damaging the coil.[1][2]
- 3Damaged coil wiring or connector, often because oil seeps in through the connector.[1][2]
- 4Power supply fault, such as a relay or a fuse, or, very rarely, the ECU.[2]
Symptoms
- Engine warning light on.[1][2]Engine warning light: faults that cause it
- Misfires and jerking on the affected cylinder, especially when accelerating.[1][2]Jerking: faults that cause it
- Uneven idle.[1][2]Vibrations: faults that cause it
- Loss of power from a cylinder that is not working.[1][2]Less power: faults that cause it
- Increased fuel consumption.[1][2]Uses more fuel: faults that cause it
How to diagnose P0351
In order: from the most likely and cheapest to check to the most expensive.
- 1Check whether the misfire code for the same cylinder is also stored (P0301 for cylinder 1).[2]
- 2Swap coil "A" with the one from another cylinder, clear the codes and read again: if the fault moves to another cylinder, the coil is the culprit.[1][2]
- 3Remove the cylinder's spark plug and check whether it is very dirty, oily, has a cracked insulator or a worn electrode.[1][2]
- 4Check the coil connector and wiring: oil, corrosion or damaged wires.[1][2]
- 5If there are several coil codes at once, suspect a common wire or the power supply before the coils.[2]
Can I keep driving with P0351?
Garage soon
If the light flashes or there are misfires, unburnt fuel can overheat the catalytic converter and damage it; AutoDTCs recommends repairing it within a day or two and avoiding long journeys.[1][2]
Documented faults related to P0351
Known faults of specific engines and cars, with their repair cost, the affected years and their sources.
Ignition coils and spark plugs: the most serious faults by engine and car
- Medium severityFrequency: Very frequent1.4 and 1.6 16vIgnition coil failureThe individual ignition coils are the most-cited fault of the K4J/K4M in the European Renault versions: they fail frequently and cause jerking, loss of power and the engine warning light coming on. It is a cheap electrical part to replace, not internal engine damage.Appears at around 30,000 km
- Medium severityFrequency: CommonBMW N43/N46Injector, ignition coil and NOx sensor failures (N43)On the direct-injection BMW N43, failures of the injectors, ignition coils (mainly in 2007-2008 units, now rare after a BMW service action) and the NOx sensor of its lean-burn combustion have been documented. The indirect-injection N46 does not have that sensor and does not suffer these failures.
- Medium severityFrequency: Common1.0/1.2/1.4 EcotecIgnition coil failureThe ignition coils on this engine fail fairly often in the Corsa, Astra, Meriva and Adam, causing jerking, the engine warning light and, in the clearest cases, the engine running on one cylinder fewer; the garage fixes it by replacing the affected coil.Repair (garage): €150–€480Appears at around 15,000 km
- Medium severityFrequency: Common1.4 TurboIgnition coil failureThe ignition coils of the 1.4 Turbo fail fairly often on the Mokka and Meriva B, with jerking, occasional loss of power and the engine warning light on; the garage fixes it by replacing the affected coil or coils.Repair (garage): €400–€600Appears at around 47,000 km
Wiring, connectors and short circuits: the most serious faults by engine and car
- Critical severityFrequency: OccasionalBMW N62 / N63Additional turbo coolant pump with a risk of short circuit and fireIn 2011 BMW recalled 5, 6 and 7 Series, X5 and X6 models built between 2007 and 2011 because of the additional turbo coolant pump: moisture, a short circuit and, in extreme cases, a fire. In 2012 there was another campaign for a crack in the pump, with a more robust version.
- High severityFrequency: Occasional1.3 TCeBlown fuel pump fuseOn the Renault Captur II and Clio V with the 1.3 TCe engine, a 20-amp fuse can blow and leave the car without an engine. According to L'argus, in April 2021 this fault still had no factory fix; the official service centre's diagnosis includes checking, and sometimes replacing, the catalytic converter.
- High severityFrequency: OccasionalM264/M254Poorly tightened 48 V earth wiring in the mild-hybrid system (fire risk)Mercedes-Benz has issued several recalls (2022-2025) because the 12 V and 48 V earth connections of some cars with a 48 V system may be poorly tightened: resistance rises, the connection heats up and a fire cannot be ruled out. The official workshop checks them and repairs them if necessary in an hour or more.
- High severityFrequency: Occasional1.9 TDIUnit injector tappet wear and injector wiring damageOn the unit injector system, the tappets that operate the injectors can wear if the oil is not changed on time, and the injector wiring can be damaged by contact with oil, causing misfires or loss of power.
- Critical severityFrequency: CommonRover 75Seat SRS connector fault with airbag and seatbelt warning light onAuto Express warns that the Rover 75's seat SRS connector can cause the airbags to fail, and dealers were fixing it with revised connectors. The Dutch APK inspection puts the airbag or seatbelt fault warning among the most frequent defects across almost all series.
- Critical severityFrequency: OccasionalAlfa Romeo GiuliettaShort circuit from badly routed wiring that can prevent gear shifting (KBA campaign, 2010-2015)Yes: according to Germany's KBA, on Alfa Romeo Giulietta cars built between 2010 and 2015 inadequate cable routing could cause a short circuit and, as a result, gear-shift failure.
P0351 by make
Documented faults that can trigger P0351 in each make's engines and cars.
Frequently asked questions
What does code P0351 mean?
There is a fault in the primary or secondary circuit of ignition coil "A", normally the one for cylinder 1.[1][2]
Does replacing the coil fix P0351?
Often yes, but first check the spark plug and the connector: a worn plug can ruin the new coil.[1][2]
Can I drive with P0351?
You can get to the garage, but avoid using the car for long: misfires send unburnt fuel to the catalytic converter and can damage it.[1][2]
What is the difference between P0351 and P0352?
None in essence: P0351 refers to coil "A" and P0352 to "B", which corresponds to another cylinder.[2][5]
Will I pass the MOT with code P0351?
If the code has switched on the engine warning light, no: with that light on, the inspection records a serious defect, and on Euro 5 and Euro 6 cars the ITV (Spain's roadworthiness inspection, similar to the MOT) also reads the OBD diagnostic system. Repair the fault before you go; clearing the code just before the inspection does not help either, because it counts as a serious defect.[6]
Not sure what is wrong with your car? Describe what you notice in the symptom diagnosis or see all fault codes.
Sources
Every fact on this page links to its source. If you find an error, let us know.
- P0351: Ignition coil A primary/secondary circuitCarista · Technical documentation · consulted 29 October 2026
- P0351 – Ignition Coil “A” Primary/Secondary CircuitAutoDTCs · Technical documentation · consulted 29 October 2026
- p0351 DTC: Ignition Coil "A" Primary/Secondary CircuitDTCSearch · Technical documentation · consulted 29 October 2026
- On-board diagnosticsWikipedia · Other source · consulted 29 October 2026
- P0352: Ignition coil B primary/secondary circuitCarista · Technical documentation · consulted 29 October 2026
- Desmontando mitos: ¿puede pasar mi coche la ITV con el testigo de «avería motor» encendido?Diariomotor · Motoring press · published 8 March 2021 · consulted 2 October 2026 · in Spanish