Ignition coil, cylinder 1 — circuit malfunction
Where to start
The coil circuit of cylinder one. Start with the cheapest step: unplug the coil and look at the contacts, then swap the coil with a neighbouring cylinder. If the code moves with it, the coil is at fault; if it stays, the wiring or the unit is.
What the cylinder number gives you
The last digit names the cylinder: 1. That is the most useful thing in this code — it turns a search across the whole engine into a check of one cylinder.
Swap and watch. Move the coil between cylinder 1 and a neighbour, clear the code and drive. If the fault follows the part, the part is to blame. If it stays on cylinder 1, the cylinder is: the injector, compression, a valve. This is the only way to tell one from the other without taking anything apart.
⚠️ This code is about the CIRCUIT, not the spark: the connector and the wire come before the coil itself. A coil is often replaced when the trouble was a corroded contact.
How to put together a report a mechanic will actually read
How the code is built
All codes in «Ignition system and misfires»
How the app helps
CarScan reads this code from your car through an OBD-II adapter, shows whether it is active now or only stored, names the module that reported it, and puts it into a plain-text report for your mechanic.