Control unit supply voltage (U30), incorrect shut off
â–¶ How to fix
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
No system-reaction text recorded.
Diagnostic depth
Detection
The battery voltage disappears before the shutdown process is completed and the engine still is running.
Possible cause
Possible cause of this fault code is that the battery has been disconnected before the ignition voltage (U15) was switched off. Another cause can be a damaged gearbox cable harness.