Supply voltage too low from actuator 1
â–¶ How to fix
Check the control unit wiring. Contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
Detection
Supply voltage for actuator 1 (HSD1) is too low.
Possible cause
The control unit has detected less than 6 V in two solenoids in the actuator 1 circuit. This can be caused by a short circuit to earth in the actuator 1 circuit.