Hi, I'm in need of some expertise..... My 07 ram 1500 4x4 5.7 check engine light came on, pulled code p0721- so I replaced the output shaft speed sensor. A few months later, same thing happened. I got a warrantied replacement and replaced the output shaft speed sensor again. After a couple of days, the check engine light came on again with same code. I've taken it to 3 different shops and no one can seem to find the problem. They've searched the wiring high and low for shorts or grounded wires to no avail. It is an intermittent problem, after driving it around a bit sometimes the light will go away but always comes back eventually. When it's on, the transmission will not go into overdrive and hard down shift to second

Has anyone else had this problem?
Any help is appreciated!!

 

Are these FCA dealerships that you've been bringing your vehicle to, engm444?

 

Jack, one was an FCA dealership. They had it for two days and couldn't figure it out. They reset the light and said bring it in when it comes back on. Not even 30 mins after I left, I was back in there, they scanned the code and of course it was a P0721 once again. They wanted to change the output speed sensor again for a third time but I declined at the time and took it to a transmission shop, they had it for a week. They swapped the input and out put sensors, unplugged the computer, plugged it back in and reset the light. Drove it for a few days and couldn't get the light to come back on so sent me on my way. About a week later it's on again and back to the same ol' problem.

 

Thanks for the info, engm444. Any update on this situation since Monday?

My recommendation would be to bring it back to a dealership, as I've been unable to find any TSBs that could be related to your concern. It may help to try a different dealership to see if their diagnosis differs at all. If they suggest the same repair, you can advise them that it has unsuccessful previously and they may be able to tap into further resources for diagnostic assistance.

 

Fluid level correct? May have a solenoid issue.

 

I had similar symptoms but different code when my solenoid pack needed replacing. I think the code for that was P0750.