On an A0, Yes TPS issues will cause the trans to revert to min/max RPM gear shifting. Its easy enough to check with an ohm meter. It has 3 wires. The outer 2, pins A and C measure across the resistor and should read 9K-15KOhms. the center wire(pinB) varies resistance between either A or C and should mesure between 500ohms and the resistance measured across A and C when the wiper/cable end is moved from one end to the other. This variable resistance Should be smooth transition with actuator cable movement.
The TCU only really looks for readings that exceed its stored minimum(idle) and maximum(full throttle) positions Before it stores a fault code. If it is stuck in between those two places, it won’t throw a fault for this.
if it checks out with an ohm meter, you can tell the transmission controller to relearn the 0-100% throttle positions and the shift points. You first want to insure that the throttle pedal fully rotates the governor linkage between the idle and high speed stop screws.
once TPS resistance and idle to full throttle governor linkage is confirmed, run the truck to get it fully warmed up Then shut down. Cycle the power sw on until you get a trans controller display indication then switch off. Repeat this cycle 5 times, then on the 6th power on, the shift points and throttle info will be cleared. Fully depress and release the throttle pedal once or twice to store the new idle and 100% throttle position Info. Then push the start button and drive it thru all the gear ranges several times to relearn the shift points…
