Brake switch, circuit fault
â–¶ How to fix
Contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
The Allison fault code number is: P0703.The control unit prevents the gearbox from going from neutral position to drive position on refuse collection trucks.The control unit can prevent the use of the retarder if a fault on the accelerator pedal sensor has also been indicated.The fault code is cleared automatically, when the vehicle has completed 40 start-up cycles without the fault being detected again.
Diagnostic depth
Detection
The control unit has detected three simultaneous accelerations along with an indication that the vehicle service brakes are activated.
Possible cause
Incorrect signal from brake switch.