[ramvan2500]

My check engine light just came on, so I went to Auto Zone and had it checked. Turns out it's an output speed sensor (OSS) Circuit Performance.

Explanation
Engine running vehicle in drive and the ECM did not detect and OSS signal.
Probable cause
1. Failed output speed sensor
2. Open or short circuit condition
3. Corroded or moisture in connector.

So where is this speed sensor? I'm going to replace it. If that's the case.

The speed sensor is on the outside of the transmission on the drivers side on the extension housing. The thing is if the ECM isn't receiving any speed signal then the vehicle will NOT work so most likely that their is just some water on the wire or the sensor itself is faulty.

 

[ramvan2500]

Ok, replaced the sensor. Problem solved.
Engine light went off and my truck seems to shift better than it ever has since I've had it.

Good to hear it's working for you. That sensor is used not only to operate the speedometer, but it is used as a sensor for the ECM to determine the vehicle load and when to drop RPM's to let the trans shift of course this also includes the TPS. Don't forget to give me some rep points, it's been awhile since anyone has gave me some.

If you ever have a problem with the truck my door is open.