PREVOST X3-45 VIP 2015, Owner'S Manual

Page: 184 / 190

Appendix C – Allison Diagnostic Troubleshooting Codes 8
To begin the diagnostic process:
1. Bring the vehicle to a stop at a safe location.
2. Apply the parking brake.
To display stored codes:
1. Simultaneously press the (Upshift) and (Downshift) arrow buttons five times (Prognostics
enabled) to access the Diagnostic Display Mode. With Prognostics disabled, press the (Upshift)
and (Downshift) arrow buttons twice.
2. Press the MODE button to read the next code in the queue, if any.
To clear all active stored codes:
While in Diagnostic Mode, clear all active codes by pressing and holding the MODE button for
approximately three seconds until the MODE message flashes. Release the MODE button. The MODE
message should not remain illuminated if the active DTC shown in the display has cleared.
While in Diagnostic Mode, press and hold the MODE button for 10 seconds to clear both active codes and
inactive codes. The MODE message flashes a second time indicating all codes are cleared from the
queue.
Exiting Diagnostic Mode
Exit the diagnostic mode by one of the following methods:
1. Press simultaneously the (Upshift) and (Downshift) arrow buttons at the same time on the
pushbutton shift selector.
2. Press any range button «D», «N» or «R» on the pushbutton shift selector.
3. After approximately 10 minutes of inactivity at the pushbutton shift selector, the diagnostic mode
automatically exits and returns to normal operating mode.
4. Turn off power to the TCM (shut off the engine using the ignition key).
NOTE
Be sure to record all codes displayed before they are cleared. This is essential for troubleshooting.
NOTE
If clearing a code while locked in a «D» (Drive) or «R» (Reverse) position (fail-to-range), the
transmission will still be in «D» (Drive) or «R» (Reverse) when the clearing procedure is completed.
«N» (Neutral) must be manually selected.
DIAGNOSTIC TROUBLE CODE RESPONSE
The electronic control system is programmed to inform the operator of a problem with the transmission
system via the CHECK light and shift selector display while it automatically takes action to protect the
operator, vehicle, and transmission. When the Transmission Control Module (TCM) flags a Diagnostic
Trouble Code (DTC) as active, the TCM may take a combination of diagnostic responses as listed in the
table below.