Diagnostic Code Display And Clearing Procedure; Exiting Diagnostic Mode - PREVOST H3-45 2023 Operator's Manual

C-8 Allison Transmission Other Features

DIAGNOSTIC CODE DISPLAY AND CLEARING PROCEDURE

Diagnostic codes can be read and cleared by two methods:
Using an Allison DOC™ diagnostic tool. For specific instructions on how to use an Allison DOC™
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diagnostic tool, refer to the User Guide.
Using the pushbutton shift selector.
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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
access the Diagnostic Display Mode. With Prognostics disabled, press the
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
selector.
2. Press any range button «D», «N» or «R» on the push button shift selector.
3. After approximately 10 minutes of inactivity at the push button 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.
(Upshift) and (Downshift) arrow buttons five times (Prognostics enabled) to
(Upshift) and (Downshift) arrow buttons at the same time on the push button shift
PA-1652 Operator's Manual H3-45 Coach
(Upshift) and $(Downshift)