Turbine speed sensor, no signal
Check the cable harness. Try fitting a new sensor and check whether the fault disappears. Contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
The Allison fault code number is: P0717.The fault code is set when the following occurs: Unrealistically large changes (at least 800 rpm) in turbine speed.Unrealistically low turbine speed. The turbine speed is below 61 rpm and the output shaft speed is at least 500 rpm for at least 1 second.For the fault code to be set, the following conditions must be met:The control unit on the vehicle has fire engine calibration. Gear changing has been completed. Engine running.Current gear is not neutral. No basic hydraulic setting conditions because voltage has been lost. The oil sump temperature is above -1.1°C.If the fault occurs when driving with the forward gear range selected and a gear-change has been carried out, the gearbox will maintain the current gear. If the fault occurs when driving with the forward gear range selected and gear changing is in progress, the gearbox returns to the previous gear after which the gearbox carries out the requested gear-change.The lock-up cannot be locked.The control unit shuts off gear changing adaptation. The fault code is cleared automatically, when the vehicle has completed 40 start-up cycles without the fault being detected again.
Diagnostic depth
Signal from turbine speed sensor missing
A possible cause of the fault may be damage to the cable harness or a defective turbine speed sensor.