code 45 does anyone know what this code indicates

Hi Guys I have a 1997 jeep Cherokee 4.0 l aw4 tranny 4wd and the check engine light is on and I have a code 45 and can't find anything that tells me what a code 45 is does anyone know what this code indicates. thanks

Battery voltage too low and or alternator output too low.

How old is the battery, does it happen to be the original If so replace it. I did all three of ours in march or so, three new red tops, 98XJ and Two 97TJ's... advance auto has them on sale from time to time for like $100 or so... My 98's battery was OK but when the redtop went in the engine sure spun over alot faster...