Hi all. I will try to make this short. As stated I have 2016 Versa SV sedan. Battery light and brake light came on at same time and won't turn off. Removed the alternator and had it tested. Tested good. Replaced the battery after a mechanic looked at it and he said the battery was bad. Even had to jump start it when I picked it up. After the battery was replaced, the lights are still on. Is there any another reason those lights would come one and stay on? Brake fluid is and has been full. Is there some procedure to turn those lights off after something like this?

I am very confused. Thanks for any help and advice.

Did the battery light go away after battery replacement?

If so, likely a stuck brake fluid sensor.

No... Battery light and brake light are still on.

OK now the check engine light is on. So now I have the battery, brake and check engine lights on. My bluetooth scanner shows a code of P0171. It says system too lean bank 1. Not sure how this all relates to each other. I am even more confused now.

Battery or ground. If you have a multimeter (if not, and you should), test battery voltage with car off (red probe to +, black probe to -).

Then test battery voltage with the car running. Your readings should be approximately 12v and 14.7v, respectively.

Corroded terminals or a corroded ground wire can cause this as well. Inspect & make sure battery terminals are clean & tight.
Check the ground connections... there are lots of them in the engine compartment. Verify they're corrosion free & tight. If you need to clean them, clean both surfaces (metal around the hole and the terminal itself) with a wire wheel, apply dielectric grease & tighten.

Sorry for not posting this before.... I don't know the correct terminology. But it turned out to be one of the computers ander the hood. It was near the firewall on the drivers side. Apparently it was supposed to send out signals between 1 and 5 volts to various componenets. It was just sending a strait 5V. This caused all my problems and caused my alternator to overcharge my battery and ruined the battery. it was throwing so many codes, too lean, too rich etc. My gas milage went way down. The part cost $700 and $100 for him to progam it. This car has never ran better. Since then my gas milage has gone up from 38mpg to 41mpg. I was impressed with the 38. I had no idea I could get even more.

So im sorry I dont know the name of the part, but I hope this may help someone if they read it.