Allison B 300 - Clearing Active Indicators; Manually Clearing Codes and Active Indicators from the Code List

6–2 Copyright © 1998 General Motors Corp.
DIAGNOSTIC CODES
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
NOTE: If a DO NOT SHIFT condition is present at this time, the shift lever should remain in the same
position where it was when the DO NOT SHIFT was detected. If the lever is moved, a continuous tone
will be heard until the lever is returned to the correct position.
NOTE: If an oil level sensor is present, then fluid level will be displayed first. Diagnostic code display is
achieved by depressing the ⇑ ( Up ) and ⇓ ( Down ) arrow buttons or the DISPLAY MODE button a
second time.
The code list position is the first item displayed, followed by the main code and the Subcode. Each item is
displayed for two seconds. The two second item display cycles continuously until the next code list position is
accessed. The following list represents the display cycle using Code 25 11 as an example:
1. Code list position — d1
2. Main code — 25
3. Subcode — 11
4. Cycle repeats — d1
To view the second, third, fourth, and fifth positions (d2, d3, d4, and d5), momentarily press the MODE button as
explained above.
Momentarily press the MODE button after the fifth position is displayed to restart the sequence of code list
positions.
An active code is indicated by the MODE ON indicator (active indicator) illuminating when a code position is
displayed. In the normal operating mode, the MODE ON display indicates secondary mode operation.
Any code position which does not have a diagnostic code logged will display “– –” for both the main and
Subcodes. No diagnostic codes are logged after an empty code position.
B. Clearing Active Indicators. A diagnostic code’s active indicator can be cleared, which allows the
code to be removed from the code list.
The active indicator clearing methods are:
1. Power down — All active indicators, except Code 69 34 (refer to the code chart), are cleared at
ECU power down.
2. Self-clearing — Some codes will clear their active indicator when the condition causing the code
is no longer detected by the ECU.
3. Manual — Some active indicators can be cleared manually, while in the diagnostic display mode,
after the condition causing the code is corrected.
C. Manually Clearing Codes and Active Indicators from the Code List. To clear active indicators or
all codes:
1. Enter the Diagnostic Display Mode.
2. Press and hold the MODE button, approximately three seconds, until a tone sounds once. All
active indicators are cleared. To remove all codes, press and hold the MODE button for ten
seconds until the shift selector tone sounds twice. All codes will be cleared at ECU power down.
CAUTION:
If an active indicator is cleared while the transmission is locked in a forward range or
reverse (fail-to-range), the transmission will remain in the forward range or reverse after
the clearing procedure is completed. Neutral must be manually selected.