TOYOTA

A: Toyota ignition coils generally last for 100,000 to 150,000 miles, but the lifespan varies significantly based on factors like driving conditions, maintenance habits, and the quality of the components. You can inspect them around 60,000 to 100,000 miles and replace them if you notice signs of failure, such as engine misfires or a Check Engine light.

A: Ignition coils often fail due to heat damage and faulty spark plugs causing coil overload. Repeated #1 ignition coil failure can stem from worn spark plugs causing excessive coil stress. Inspect and replace spark plugs with correct gap specifications.

A: Fortunately, replacing ignition coils is a fairly straightforward repair you can do at home with a few tools.

A: You don't always have to replace ignition coils with spark plugs, but it's often a good idea to do so if the spark plugs are difficult to access, as a failing spark plug can damage a coil, or if you want to prevent future issues. Spark plugs are routine maintenance items that wear out with normal use, while ignition coils are typically only replaced when they fail and cause a misfire.

A: You can tell if an ignition coil is bad by recognizing symptoms like engine misfires, a rough idle, reduced power or sluggish acceleration, a check engine light, poor fuel economy, and a strong fuel smell from the exhaust or backfiring. Other signs can include difficulty starting the engine or the engine stalling.

A: Yes, a bad ignition coil will almost always trigger a check engine light and set a Diagnostic Trouble Code (DTC), typically a P0300-P0312 for a misfire or a P0350-P0362 for a circuit malfunction. The engine control module (ECM) detects the misfire caused by the faulty coil, illuminating the check engine light to inform the driver of the issue.