WTEC III ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL DIAGNOSTIC CODES Copyright © 2001 General Motors Corp. 3. Manual — Some active indicators can be cleared manually, while in the diagnostic display mode, after the condition causing the code is corrected. 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. 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 for approximately three seconds until the LED indicator flashes. All active indicators are cleared. To remove all inactive codes, press and hold the MODE button for about ten seconds until the LED indicator flashes again. All active indicators will be cleared at ECU power down. 3. Codes that cannot be manually cleared will remain. D. Exiting the diagnostic display mode. Exit the diagnostic display mode using one of the following procedures: 1. On a pushbutton shift selector, press the ⇑ (Up) and ⇓ (Down) arrow buttons at the same time or press any range button, D, N, or R. The shift (D, N, or R) is commanded if not inhibited by an active code. 2.
On a lever shift selector, momentarily press the “display mode” button or move the shift lever to any shift position other than the one it was in when the diagnostic display mode was activated. If the shift is inhibited, the ECU will continue to command the current transmission range attained and the lever should be returned to its original position. 3. Wait until timeout (approximately 10 minutes) and the system will automatically return to the normal operating mode. 4. Turn off power to the ECU (turn off the vehicle engine at the ignition switch). 6–3. DIAGNOSTIC CODE RESPONSE The following ECU responses to a fault provide for safe transmission operation:
• Do Not Shift (DNS) Response — Release lockup clutch and inhibit lockup operation. — Inhibit all shifts. — Turn on the CHECK TRANS light. — Display the range attained. — Ignore any range selection inputs from the pushbutton or lever shift selector. • Do Not Adapt (DNA) Response — The ECU stops adaptive shift control while the code is active. Do not adapt shifts when a code with the DNA response is active.