How to Diagnose a Bad Ignition Coil: Symptoms & Solutions

An ignition coil is a crucial component in your vehicle's ignition system. It converts the battery's low voltage into the thousands of volts needed to create an electric spark in the spark plugs, igniting the fuel.

Common Fail Symptoms

• Engine Misfires: The vehicle struggles to accelerate or runs rough.
• Poor Fuel Economy: Unburnt fuel wastes energy.
• Check Engine Light: Fault codes like P0300 to P0308.

How to Test

Use a multimeter to measure the resistance of the primary and secondary windings. Compare the ohm readings with the manufacturer specifications (typically 0.5-2 ohms for primary, and 6,000-15,000 ohms for secondary).