WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL DIAGNOSTIC CODES The diagnostic display mode may be entered for viewing of codes at any speed. Active codes can only be cleared when the output speed = 0 and no output speed sensor failure is active. A. Reading Codes. Enter the diagnostic display mode by pressing the Up ) and Down ) arrow buttons at the same time on a pushbutton selector, or by momentarily pressing the “display mode” button on a lever shift selector. NOTE: If a DO NOT SHIFT condition is present (CHECK TRANS light illuminated) at this time, the shift selector may or may not respond to requested range changes. NOTE:
If an oil level sensor is present, then fluid level will be displayed first. Diagnostic code display is achieved by simultaneously depressing the Up ) and Down ) arrow buttons a second time or the “display mode” button a second time. The code list or queue position is the first item displayed, followed by the main code and the subcode. Each item is displayed for about one second. The display cycles continuously until the next code list position is accessed by pressing the MODE button. The following list represents the display cycle using code 25 11 as an example: 1. Code list position — d , 1 2. Main code — 2 , 5 3. Subcode — 1 , 1 4.
Cycle repeats — d , 1 , 2 , 5 , 1 , 1 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 illumination of the LED indicator when a code position is displayed while in the diagnostic display mode. In the normal operating mode, the LED indicator illuminates to show a 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 inhibit to be cleared but remains in the queue as inactive. 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. Copyright © 2001 General Motors Corp.