My 2001 Nitro sat for about a year, batteries are charged but it doesn't start.

when a battery is completely drained, it shortens the life or could kill it all together. Time for a new one. Doesn't need to be coded.

Have you checked for a parasitic draw on the system . Something draining the battery .

Have the battery tested an the charging system as well .

There is a fusible link inline of the heavy gage wire to the back of the alternator. The heavy gage wire come's off the starter solenoid . Fusible link will be near the soleniod connection . The smaller gage wire's come from the PCM - engine computer . The alternator is computer controlled .

Dead Battery --Replace it

Fix your car right away by clicking the link I attached 2001 Jeep Wrangler

Hello and welcome to FixYa!

As a first course of action, I strongly suggest that you have the battery charged. It can be an indication of a weak battery or a faulty alternator. If the battery light still on after charging then the problem will surely be on the alternator itself. If that's the case the alternator should be replaced to resolve the problem.

You may try to reset it to by removing the positive battery connector, letting it sit for at least 5mins. then reconnect it again. This will reset the system and can get the battery light off.

Hope this helps and thank you for using FixYa! Have a good one!

Sounds like the battery is old and got hot from all of the use and charging that was put on it. Next time you drive the car a bit, check the battery with your hand. Be careful it may be really hot. If it is too hot to touch, replace it.

If checking battery cables and wiring to the starter and ground points doesn't help. Have the battery checked for a bad cell. Preferably before you charge it.

Sounds like a battery problem mate, give the battery a charge and see how it goes, If it has been sitting for a while it sounds like it might be a carby problem, so clean out your air filter, give her an oil change and give the carby a clean and then try kicking her over with a fully charged battery