Ok. Heres the deal. I was sitting in traffic in Vegas and all of a sudden my truck dinged and threw a CEL. So I pull out Smarty and it says P1750 Transmission Throttle Valve Position Sensor Circuit High. try to clear it but it doesnt work. Get to the track and try again, except now I had P1749 Transmission Throttle Valve Position Sensor Circuit Low. Can only clear one, but not the other.

So now my truck has defueled a bunch. I was able to black out an intersection if I wanted, and now can barely get more of a haze than stock. Was pushing 40psi, now Im at 30. Truck shifts REAL hard into second, and has very little power. Itll go down the highway fine, but Id say its a little elow stock power.

What do I need to check or do? I replaced the trans filter and fluid before the trip, filled with fresh Amsoil. At the time it threw the code, I was creeping along stop-and-go heading to the track in Vegas, and temps were pushing 210-220. I put it in neutral a couple times to take the load off the trans in an effort to cool it. If its that warm, and I can smell transmission fluid, its to dang hot.

Kinda lost on what to do, and Id like to avoid the dealership. The local one I wont use, and the other one thats helped me before is 150 miles away. Thanks guys

 

The Transmission Throttle Valve Actuator (TTVA) does not require any mechanical adjustments. All changes in throttle valve position are controlled by the Engine Control Module (ECM).

The TTVA does require an initialization period after the actuator has been removed or replaced. After the actuator has been removed or replaced, move the iginition to the ON position for thirty (30) seconds. This will allow the ECM sufficient time to perform the internal calibration procedures to learn the TTVA's current “zero” position. Once this is done, check the ECM for diagnostic trouble codes (DTCs). If no DTCs are set relating to the TTVA, the TTVA is fully calibrated and ready for use.
On vehicles equipped with a Cummins diesel engine, the transmission throttle valve cable has been replace by the transmission throttle valve actuator (TTVA). The TTVA consists of an electric DC motor, two potentiometers, and a gear drive system. The TTVA is mechanically connected to the transmission throttle valve in the valve body by the “D” shaped opening in the bottom of the TTVA shaft. Changes in the TTVA position are therefore transferred to the throttle valve and cause changes in the transmission throttle pressure.
Most of the time Transmission throttle valve actuator is problem. Easy to change but if you are still under warranty might want to take to dealership.
Possible Causes
(K312) TTVA POSITION SENSOR SIGNAL CIRCUIT SHORT TO VOLTAGE
(K312) TTVA POSITION SENSOR SIGNAL CIRCUIT SHORT TO ANOTHER CIRCUIT
(K900) SENSOR GROUND CIRCUIT OPEN
TRANSMISSION THROTTLE VALVE ACTUATOR
ENGINE CONTROL MODULE

 

Ive read that before, but doesnt really have any trouble shooting. Trucks not under warranty. Any idea how much a TTVA costs? Any idea how to narrow it down to either the TTVA, ECM (Im guessin its not this, cause truck runs good other than the fuel being pulled back) or a circuit issue?