30 voltage control unit, interference
Check the battery and associated cable harness. Ensure that the cable harness between gearbox and control unit is not damaged. If no fault is found, contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
The Allison fault code number is: P0881.For the fault code to be set, the engine speed must be higher than 500 rpm for more than 1.5 seconds.The fault code is cleared automatically, when the vehicle has completed 40 start-up cycles without the fault being detected again.
Diagnostic depth
The control unit has detected that the 30 voltage varies widely.
The cause of this fault code can be: Fault on the vehicle battery.Corroded electrical cables on the battery.Loose contact or damaged cable harness.Internal fault in the control unit.