Cadillac Repair: check engine light, cadillac seville, trouble tree

Question
How does this come on. while driving mountains going down hill shifting down and braking my check engine light comes on. I disconnect the battery light goes out. It does not re turn until I get in the mountains again.My car is a 1999 cadillac seville. Cadillac says transmission but transmission makes no noise does not miss gears everything seem good

Answer
Hi Richard, It is tough to advise on this one because you don't tell me what the code is that caused the light to turn on. The reason a code turns on the service light is because something that the computor controls or a mechanical device isn't working like it was designed. Useing your example that could mean a bad transmission, a bad sensor inside the trans or a loose wire connection or open wire between the trans and the computor. It could still be working but be slower to change or react and that turns on the light. Only by following a trouble tree and testing can it be determined what has failed. Auto Zone can scan the codes for free but to get to the reason the light is on you will need to follow the advise of the shop you trust because it might not be a part problem but a loose wire connection or open/shorted wire. The other thing you can do is since you only get the light to turn on when driving hills and the trans seems ok to you is to continue to drive it until the trans acts up or the light starts comming on all the time. Sorry I can't be more help than that. Bill