Could be a leaking injector seal but would be there even when not under load. You probably need to try and isolate if it’s from the engine itself or an ancillary like a drive belt pulley.
Blue smoke would indicate oil burning, does it use much? Never seen one needing valve stem seals, more...
They don’t have a big battery on the petrol engines so probably fine if you’re not having any issues
Only use genuine Honda ATF, it’s not very expensive.
Stick to genuine Honda plugs
Sorry I didn’t read your post thoroughly. I would say it’s either battery or alternator again then. These use a smart alternator it’s possible the clutch on it is defective
If you can get it on a Honda hds system it will show which sensor triggered the last few alarm events. Often it’s the bonnet sensor which you can just disconnect. You can book with me if you’re local to the north of England.
That’s why i said swap the complete rail. A sticking relief valve can cause high fuel pressure error too, either swap both parts to your current rail or just source a used one with parts attached.
Sounds more like a faulty fuel rail pressure sensor. Sometimes cheaper and easier to find a secondhand fuel rail with the sensor and relief valve attached and just swap that over. Doesn’t need to be a Type S, a standard 150bhp fuel rail will work.
Could be a sticking egr valve. Try temporarily blanking it at the inlet manifold side. You’ll get an error but you can clear it off with a basic code reader just for the purpose of this test. If it works then consider an egr off permanent solution, drop me a line if you want details.
You can hit around 215bhp with a quality intercooler. Type S turbocharger has a different internal core and cylinder head, not to mention a stronger clutch.
Yes the CMBS relies on inputs from various sensors and systems to be able to operate correctly, you should always run a diagnostic to determine the cause and takeout any guesswork.