New to this site as of yesterday. I have read on this site several inquireries about the check engine light coming on when temps drop below freezing. My truck also will not shift into overdrive. There are times that if I pull over after a couple of miles and shut off and restart it will shift but the light stays on until the outside temp gets above freezing for a while. Other times I have to drive it 15-20 miles and it will shift into overdrive after letting of the gas but light stays on and goes off when temp rises. It always seems not to happen after I schedule service with local dealer. I ask them what they think is wrong and I always get the response that " we need to see it when it happens to be able to diagnose " ( want more of my money ). Any suggestions on what it might be and can I fix myself. I have a 2004 cummins 3500 swd quad cab long bed 4x4, 100,000 miles. Love the truck but this is a pain in the *** during cold periods.

 

welcome to DTR. use the signature feature on the user cp page to add the portion of your post with your truck info. it will then show up on each post.

turn your key on and off 3 times and back to on. read the odometer. the codes will be p****. example will be P0514, which is the common low temp battery code. when you get the codes, come back to the site and use the search feature to find the code your truck gives you and start reading.

if no codes are stored, the odometer will read done

 

Thanks for the info. P2127 pedal validation switch 2 low. Any idea what that has to do with tranny shifting? P0483 not showing up now. I think I am going to wait until it gets below freezing again then check the codes. Will post findings if any.

 

Same thing happens with my 04.5 auto and has been getting worse every winter. I lose overdrive three or four times a day when it is 4 degrees Ceslius or lower. I took all pcm and ecm plugs out and cleaned them out this summer. Even used dielectric grease on all sockets and it still does it. Might have to break down and buy a new apps. Costing me too much in fuel! Unless someone else knows a magic fix. Anyone????????????????????????