As with ANY electrical problem: start at the battery, then battery cable connections.I'm also having the same problem. First started in the Winter where my 15 Si wouldn't start on the 1st try. Didn't think much of it. It would start on the 2nd or 3rd try. OK fine. It did that occasionally. Then finally it wouldn't start anymore last Monday. It would start with a jump so I went and got a new battery. It would start on the 1st try no big deal. Come Wednesday wouldn't start anymore again. It would start with a jump. I text my friend who owns a shop and he says to bring it in the next day so he can do a bit of trouble shooting. Thursday I get my 2nd COVID shot, drop the car off at my friends and the Check Charging System warning comes up. He says it's most likely the alternator. He then does some readings and sees that he can hear my starter click and then changes his mind and says it's the starter. Hooks up a scanner and says that I may need a new battery sensor too. Now this is where it confuses me, if the car can start with a jump, why would it be the starter? At this point I'm starting to feel the side effects and said **** it. I'll just leave it at Honda so they can properly diagnose it. Leave the car at Honda and they say it's the starter but no starter around. They would have to order it and won't be installed until Mon/Tuesday. I'll keep you guys posted. Also no electric mods.
Did anyone check the battery voltage as the starter was engaged?
(battery voltage should never drop below 12V when cranking the engine.)