Skip the auto shop - Our mechanics make house calls

Symptoms of a Bad or Failing Ignition Coil

ignition cable

Bad or Failing Ignition Coil Inspection

by a top-rated mechanic at your home or office

Ignition coils are an electronic engine management component that are a part of the vehicle’s ignition system. The ignition coil functions as an induction coil that converts the vehicle’s 12 volts into the several thousand that are required to jump the spark plug gap and ignite the engine’s air-fuel mixture. Some ignition systems will use one coil to provide the spark for all of the cylinders, however most newer designs use an individual coil for each cylinder.

As the ignition coil is the component responsible for generating the engine spark, any problems with it can quickly lead to engine performance issues. Usually a faulty ignition coil will produce a few symptoms that alert the driver of a potential issue.

HAVE SYMPTOMS OF CAR TROUBLE?
Get an $80 diagnostic
by a top-rated mechanic at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

1. Engine misfires, rough idle, and loss of power

One of the most common symptoms associated with a faulty ignition coil is engine performance issues. As the ignition coils are among the ignition system's most vital components, an issue can cause spark to be compromised, which can quickly lead to performance issues. Faulty coils may cause the vehicle to experience misfires, a rough idle, a loss in power and acceleration, and a reduction in gas mileage. In some cases the performance issues may even result in the vehicle stalling.

2. Check Engine Light comes on

Another symptom of a potential issue with the vehicle’s ignition coils is an illuminated Check Engine Light. Faulty coils can lead to engine performance issues, particularly misfires, which will trip the computer and set off the Check Engine Light. The Check Engine Light will also be set off if the computer detects an issue with the ignition coil signal or circuit, such as when a coil burns out or shorts. An illuminated Check Engine Light can be caused by a wide variety of issues, so having the computer (scanned for trouble codes)[https://www.yourmechanic.com/services/check-engine-light-is-on-inspection] is highly recommended.

HAVE SYMPTOMS OF CAR TROUBLE?
Get your car fixed at your home or office.

Get a quote · Book an Appointment · Our expert mechanics come to you.

3. Car is not starting

A faulty ignition coil can also lead to a no-start condition. For vehicles that use a single ignition coil as the source of spark for all of the cylinders, a faulty coil will affect the operation of the entire engine. If the coil fails completely, it will leave the engine without spark, which will result in a no spark, no-start condition.

Problems with ignition coils are usually easy to detect as they produce symptoms that will be quite noticeable to the driver. If you suspect that your vehicle’s ignition coils are having an issue, have the vehicle inspected by a professional technician from YourMechanic to determine if any coils need to be replaced.

The statements expressed above are only for informational purposes and should be independently verified. Please see our terms of service for more details
Still not sure about your car's issue?
Diagnose your car
What kind of issue are you experiencing?
Brakes are squeaking
Car is not starting
Car is overheating
Car is shaking (vibrating)
Fluids are leaking
Heating and A/C
Smoke or steam is coming out of the car
Warning light is on
Icon-warranty_badge-02

Skip the repair shop, our top-rated mechanics come to you.

At your home or office

Choose from 600+ repair, maintenance & diagnostic services. Our top-rated mechanics bring all parts & tools to your location.

Fair & transparent pricing

See labor & parts costs upfront, so you can book with confidence.

12-month, 12,000-mile warranty

Our services are backed by a 12-month, 12,000-mile warranty for your peace of mind.

Get A Quote

Need Help With Your Car?

Our certified mobile mechanics make house calls in over 2,000 U.S. cities. Fast, free online quotes for your car repair.

GET A QUOTE

More related articles

P2159 OBD-II Trouble Code: Vehicle Speed Sensor B Range/Performance
Diagnostic Trouble Code (DTC): P2159 P2159 code definition Vehicle Speed Sensor B Range/Performance...
P2422 OBD-II Trouble Code: Evaporative Emissions Control System (EVAP) Vent Valve Stuck Closed
Diagnostic Trouble Code (DTC): P2422 P2422 code definition Evaporative Emissions Control System (EVAP)...
What are the Car Pool Rules in Hawaii?
Hawaii is widely regarded as a land of vacation and relaxation, and as such, its scenic roads and routes are far better known than the state’s freeways. But, as with all...


Related questions

Q: Rough idling

Hi there. Most of the time, this is caused by a dirty throttle body. If there is build up in the throttle body bore, then the throttle plate will have trouble racing the correct location keeping the engine from maintaining...

Q: Can clearing a code affect the idle air control valve

If the codes were cleared and idle learn was reset then it may take a day or two to relearn the idle again and will have erratic idle until then. If after a couple days still runs rough or stalls...

Q: Car keeps shutting off while im driving but cranks right back up in 3 minutes

If the car just shuts down with no warning, sputtering,etc, it sounds like your ignition switch is failing. It will not set any fault codes or turn the Check Engine Light on. There was a recall on a number...