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On-Board Diagnostic System Check: Testing

WARNING: This page is about a different car, the 1994 Cadillac Fleetwood. However, it is still accessible from the selected car via links, so may be relevant.
  1. Turn ignition switch to RUN position. Enter diagnostic mode by simultaneously pressing OFF button and TEMP UP button on H-A/C control panel. Press fan up/down button and select "-02" for HVAC DTCs. Press OUT TEMP button to display HVAC DTCs. Note any DTCs present.
  2. If DTC 26 is present, diagnose and repair before checking for CCM, SIR and ABS/TCS DTCs. See A/C-HEATER SYSTEM article then go to next step. If no DTCs are present, go to next step. If diagnostic mode can not be entered and H-A/C control panel does not illuminate, diagnose and repair H-A/C system as necessary.
  3. Check for DTCs in other systems by pressing fan up/down button and selecting "-00" for PCM DTCs, "-01" for CCM DTCs, "-03" for SIR DTCs and "-04" for ABS/TCS DTCs. Note any DTCs present for each respective system. Code tests in this article are only for CCM system, (codes retrieved under pointer "-01"). For codes retrieved under other pointers, see related article in approriate section. If no DTCs are present, check control module for proper terminal connections.
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