30 voltage control unit, incorrect shut off
Check that the cable harness between the gearbox and the control unit is not damaged.Contact an Allison dealer.
What you'll see
No driver-visible symptom recorded.
System reaction
The Allison fault code number is: P0880.The fault code is set during a future start up when the battery voltage is lost before the previous shut off process is completed. This check is carried out continuously. The control unit loses gear shift adaption information gathered during driving. The control unit reverts to the last saved adaption values. The fault code is cleared automatically, when the vehicle has completed 40 start-up cycles without the fault being detected again.
Diagnostic depth
The battery voltage disappears before the shutdown process is completed and the engine still is running.
Possible cause of this fault code is that the battery has been disconnected before the 15 voltage was switched off. Another cause can be a damaged gearbox cable harness.