Appendix B - ATEC Transmission Codes
Foretravel Owners Manual
Page B-1
Rev. 06-02
ALLISON TRANSMISSION DIAGNOSTIC CODES
WORLD TRANSMISSIONS
ON HIGHWAY DIAGNOSTIC CODES
Illumination of the CHECK TRANSMISSION light during vehicle operation (start-up), indi-
cates that the ECU has registered a diagnostic code. The general procedure to display the codes is
to first enter the diagnostic mode. This is accomplished by pressing the upshift and downshift ar-
row buttons simultaneously on the push-button selector. A diagnostic mode will be entered only
with the vehicle stopped. (The transmission should be shifted to NEUTRAL and the vehicle park-
ing brake applied.) For each code stored in memory, beginning with any code that is presently in-
hibiting the transmission, the 4 digits of the code and the pertinent parameters are continuously
flashed on the display. Pressing the mode button once will cause the next code with its pertinent
information to be displayed. Dashes indicate all stored codes have been displayed.
To clear any active inhibits, the mode button must be depressed and held until 1 beep is sound-
ed. To clear the code from memory, the mode button must be pressed and held for a longer period
of time (Second beep is sounded). All active inhibits will also be cleared during a normal power-
down (ignition switched off followed by zero output and zero engine speeds).
A summary of diagnostic codes can be found in your Allison Transmission Owner’s Manual.
