Car model and year: 2014 Ram 1500 Express Crew 4WD 5.7L
serv 4wd light came on and will not shift to 4wd. Some slush/ice got stuck up around the shift linkage and had a little trouble shifting to park. After running the shifter up and down the gears a few times it went to park without a problem. But, if I turn off the truck and start it again, there’s a 2-3 second gap when between starting and the light coming on that I can shift to 4wd. And it will drive and function in 4wd just fine. But as soon as the knob is turned back to 2wd the light reappears and 4wd is lost until the truck is killed and restarted. Another note,every few starts i get a low pressure on the driver front tire and after 5-10 seconds it updates and shows the correct psi.
How to do?
Just being a backyard mechanic I can’t say for sure, but it sounds like a computer or electronics issue. I always like to start simple. A real mechanic once told me to disconnect both battery cables, then hold the positive and negative together for about 5 seconds. Then just let the vehicle sit (with battery still disconnected) for 30 minutes or so. That should reset the computer, much like rebooting your home computer will solve a lot of issues. I’ve done this a number of times on both my rams and it’s amazing how many times it’s worked. If you do this, you might find that the engine idle will be a bit rough, but that will smooth out after a few days.
Since you mentioned some ice and snow packed under there, you might want to crawl underneath and check the wiring and connections. Something might have loosened or corroded…hopefully it’s something as simple as that.
You also might want to invest in a scanner. I purchased a Foxwell NT530 scanner for 159usd and it’s helped me out a lot. Lots of times something real simple will trigger a computer module and a code will pop up. You can clear most codes with a scan tool, and if they pop up again, then you can narrow down the problem. If they don’t show up again and everything runs as it should, problem solved. Unfortunately some issues reach the point where a mechanic is needed. 🙁
Good to know:
Foxwell NT530 scanner from foxwelltool.com only 159usd (5th anniversary sale)