Ignition coil, cylinder 2 — circuit malfunction
Where to start
The coil circuit of cylinder two. The same move as with P0351: swap the coil to a neighbouring cylinder and see whether the code follows. If it moves, the coil is to blame; if it stays, the wiring or the unit itself is. On inline engines cylinder two is counted from the pulley end; on V engines the numbering runs by banks and is worth checking against a diagram — mixing up two and five is easier than it sounds. P0302 usually sits next to it, a misfire in the same cylinder; if that one is absent while the coil code is present, the trouble is in the circuit rather than in the burning.
What the cylinder number gives you
The last digit names the cylinder: 2. 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 2 and a neighbour, clear the code and drive. If the fault follows the part, the part is to blame. If it stays on cylinder 2, 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.