1998 Cadillac CateraFACTORY OEM SERVICE PROCEDURE

DTC B1973: High Power Control Fault: Testing

  1. If BCM system check was performed, go to next step. If BCM system check was not performed, go to BCM SYSTEM CHECK  .
  2. Disconnect BCM 32-pin C2 connector. Disconnect multifunction relay module. See Figure . Using DVOM, check voltage at BCM connector C2, terminal D01 (Brown/Blue wire). Turn ignition switch to ON position. Check voltage reading. If both voltage readings are less than one volt, go to next step. If both voltage readings are not less than one volt, go to step 4).
  3. Check for poor connection at BCM connector C2, terminal D01 (Brown/Blue wire). Check all BCM power and ground circuits. See WIRING DIAGRAMS. Reinstall all disconnected components and connectors. Using scan tool, clear codes. Check for codes. If DTC B1973 is set, go to step 5). If DTC B1973 is not set, go to BCM SYSTEM CHECK  .
  4. Repair short to battery in Brown/Blue wire between multifunction relay module and BCM. Perform BCM SYSTEM CHECK  .
  5. Replace BCM. See BODY CONTROL MODULE (BCM)  under REMOVAL & INSTALLATION. Reprogram BCM. See PROGRAMMING  . Perform BCM SYSTEM CHECK.
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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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