Hi and thank you for your question.
Please bear with me as I delve a little deeper into the symptoms you are experiencing.
When you say you have no fire, do you mean no fire to the spark plug?
If yes, what method are you using to check spark?
Also, if yes, have you tried a new spark plug?
If that is not what you mean, are you saying the engine won't turn over?
Code 46 is abnormal voltage to the fuel injection. It would start and run if that were the only problem. That leads us to believe it is something else that is preventing the ATV from starting.
Would you please provide background on this ATV also?
Things like, have you ever had it start normally or did you just acquire it?
How long has it been since it has started normally?
What prompted you to replace the battery?
Did it quit while riding or was it running fine the last time you rode it and then would not start the next time you tried?