Copyright © 1998 General Motors Corp. 3–3
BASIC KNOWLEDGE
WTEC II ELECTRONIC CONTROLS TROUBLESHOOTING MANUAL
3–5. BEGINNING THE TROUBLESHOOTING PROCESS
NOTE: Whenever a transmission is overhauled, exchanged, or has undergone internal repairs, the
Electronic Control Unit (ECU) must be “RESET TO UNADAPTED SHIFTS.” See Service
Information Letter 16-WT-96, Revision A for further details.
1. Begin troubleshooting by checking the transmission fluid level and ECU input voltage. Remember
that some problems may be temperature related. Do troubleshooting at the temperature level where
the problem occurs. Check diagnostic codes by:
• Using the shift selector display.
• Using the Pro-Link
®
9000 diagnostic tool.
2. When a problem exists but a diagnostic code is not indicated, refer to the Performance Complaint
Section for a listing of various electrical and hydraulic problems, their causes, and remedies.
3. If a diagnostic code is found in the ECU memory, record all available code information and clear the
active indicator (refer to Section 6).
4. Test drive the vehicle to confirm a diagnostic code or performance complaint.
• If the code reappears, refer to the Diagnostic Code section (Section 6) and the appropriate code
chart. The Diagnostic Code section lists diagnostic codes and their description. Locate the
appropriate troubleshooting chart and follow the instructions.
• If the code does not reappear, it may be an intermittent problem. Use the Pro-Link
®
and the code
display procedure described in Section 6. The code display procedure will indicate the number of
times the diagnostic code has occurred. Refer to the troubleshooting chart for possible cause(s) of
the problem.
• Appendix A deals with the identification of potential circuit problems. Refer to Appendix A if a
circuit problem is suspected.
NOTE: Information concerning specific items is contained in the appendices located in the back of this
manual. The appendices are referred to throughout the manual.
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