So yesterday i started to notice that, when i slow the truck down to about 20 mph and take a left or right turn (not coming to a complete stop) it down shifts into 1st gear and drags it to about 25 miles per hour. And a few times, it has slipped into neutral while cruising at about 55 mph. Also, when in 4th gear, after the TPS kicks in, dropping the rpms down about 400rpms, its not staying there. The RPMs go back up, then down, then up then down. All power is gone, engine screams but no go..Codes i am getting are:

P0721 OUTPUT SHAFT SPEED SENSOR CIRCUIT RANGE/PERFORMANCE

P0722 OUTPUT SHAFT SPEED SENSOR CIRCUIT NO SIGNAL.


Was hoping to get some suggestions before i start digging into sensors and or bringing it to the transmission shop for an outrageous bill that i may have been able to fix on my own. This is pretty much got my hair standing on end because of the actions my transmission is starting to do. Any info would be much appreciated as always!


In addition: It seems as though the transmission doesn't know what its doing. When i do a 0-60 soft acceleration it shifts nice and smooth. When i do the break/gas slip check, it doesn't slip. I cant find any blown fuses. Could the speed sensor cause this?

 

Vehicle speed sensor (VSS)

This may also be known as an output speed sensor (OSS). This sensor sends a varying frequency signal to the TCU to determine the current speed of the vehicle. The TCU uses this information to determine when a gear change should take place based in the various operating parameters.



~ So after doing the research i should have done before i made this thread, i strongly feel this may be the problem...i hope...

 

Bump ~ got a new OSS sensor and cleared codes several times and P0721-22-23 come back instantly...Problem still occurs.

 

Your DTC's point to a circuit fault down below. Anytime you get a circuit fault like that, it's usually a wiring or connector fault and not the sensor itself.

Clean the relevant connectors down below real good w/electrical cleaner and look for any chaffed wires.

 

Alright will do! Also i noticed my fuel gauge isn't working correctly and on my Edge, my Average and Instantanious MPH arent working as well. Is that the OSS as well?

Also, not sure its a big deal but the OSS out of my 4.6s Trans was swapped into my 02' 54's trans, i have read that people who do the swap get new connecters and use the correct OSS for that trans, is this a must?

 

So why did you swap sensors ? I'm not sure what that will do, but if didn't have problems right away, then I would guess that's not to be the problem.

Yea erratic and confused shifting is usually a TPS problem most of the time. Your DTC's have narrowed it down to, ~circuit/wiring/connection~

Yea, I'm not sure why you would swap connectors or need new ? Regardless, you know what you have to check.

 

Because the sensor on the 2002 transmission was a different size plug from the 1999 harness/transmission i have on my truck so instead of cutting and replacing the plug i just swapped the sensors.

 

Put a meter on the plug itself with the key in the ON position and it tested .6 Volts. I am not sure what i am looking for here, if its a "Strong enough current" or just a current at all.

 

But it the same trans as before right , 4r70w or a 4r100 ?

 

Yes 4r70w

 

So i brought it to the shop and they are saying its within the wiring yet i got AC voltage from the wire before i brought it in...Problem still not resolved but will post when they find out!

 

Turns out my trans harness fell out of its tie and was laying on the header and melted through 5 wires...Dooh