Universal (All Makes) Vehicle (OBD-II)
Severity:Common Causes
- map[cause:Failed ignition coil with an internal short in the primary winding]
- map[cause:Short to ground in the coil control wire from the ECM]
- map[cause:Damaged wiring or connector at the coil pack]
- map[cause:Faulty ECM driver transistor controlling Coil A — less common]
- map[cause:Moisture or oil contamination inside the coil connector]
How to Fix It
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Confirm the misfire cylinder — swap Coil A to another cylinder and see if the misfire moves.
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Inspect the coil connector and wiring for shorts, damage, or oil contamination.
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Measure coil primary resistance with a multimeter — compare to spec.
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Check the control wire from the ECM to Coil A for continuity and shorts.
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Replace the ignition coil if it fails resistance testing or if the misfire follows it.
Frequently Asked Questions
What happens if I ignore P2300?
A misfiring cylinder dumps raw fuel into the exhaust. This can destroy the catalytic converter quickly. Fix it as soon as possible.
How do I know which coil is Coil A?
Coil A typically corresponds to cylinder #1. Check your vehicle's service manual for the exact coil-to-cylinder mapping.
How much does an ignition coil cost?
Individual coils usually cost $20–$80. Some shops recommend replacing all coils at the same time to prevent comebacks.