Allison tranny service light - Throttle Position Sensor Low

Code 22-12?
The ECU is receiving a voltage signal that is below normal.
There are several possibilities:
1-The sensor is miss-adjusted into the error zone.
2-There is a shorted or open circuit on the signal wire (156 blue) or the TPS high wire (124 red)
3-failed TPS
4- a very remote but possible chance that the ECU is bad.

Five volts should be supplied to the sensor on the 124 red wire. As the TPS is cycled through its range the voltage on the 156 blue wire should vary. It should no go below 0.5 volts.