Control of supply voltage (HSD3) high
â–¶ How to fix
Check the cable harness between gearbox and control unit, particularly the cable to pin 31 on the control unit. If no fault is found, contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
No system-reaction text recorded.
Diagnostic depth
Detection
The control unit has detected more than 6 V in the HSD3 circuit after two solenoids have indicated a fault.
Possible cause
This fault code may be caused by an open circuit or short circuit to battery on the cable to pin 31 on the control unit.