اختلال إشعال في المحرك

A cylinder not burning its charge properly, recorded here as a cause because of what it does downstream. Unburnt fuel leaving the cylinder ignites in the exhaust, raising temperatures far beyond design and skewing every oxygen and temperature reading after it.

So a misfire produces codes across systems that have nothing wrong with them — catalyst efficiency, exhaust over-temperature, aftertreatment faults and fuel trim errors all follow from it. Read the misfire as the cause and the rest as consequences, and repair in that order; the alternative is replacing an aftertreatment component that a still-misfiring engine will destroy again.

The flashing warning light is the module's own judgement that damage is imminent rather than eventual, and it means stop. The causes divide into spark, fuel and compression, and identifying which is the whole of misfire diagnosis: a cylinder with good compression and a healthy injector but no spark is one repair, and one with low compression is another entirely.