1998 Cadillac CateraFACTORY OEM SERVICE PROCEDURE

BCM System Check: Notes

NOTE: Use this check as the starting point for any BCM complaint. BCM is a very reliable component, and is not likely the cause of malfunction. Most malfunctions are caused by faulty wiring, connectors or components.
  1. Turn ignition switch to OFF position. Connect scan tool to Data Link Connector (DLC). Turn ignition switch to ON position. Attempt to establish communication with BCM. If scan tool communicates with BCM, go to next step. If scan tool does not communicate with BCM, go to step 3).
  2. Using scan tool, check for BCM DTCs. If any DTC exists, go to appropriate DTC test. If no DTCs exist, system is operating properly.
  3. Attempt to establish communication with other systems connected to same serial data line (PCM, RFA, etc.). If scan tool communicates with other systems, go to next step. If scan tool does not communicate with other systems, locate and repair problem in serial data line. See DATA LINK CONNECTORS in WIRING DIAGRAMS  .
  4. Ensure ignition is on. Using a test light, probe between each BCM fuse and ground. See WIRING DIAGRAMS  . If test light illuminates at all circuits, go to next step. If test light does not illuminate at all circuits, go to step 9).
  5. Turn ignition off. Disconnect BCM 24-pin connector C1 and 32-pin connector C2. Turn ignition on. Using a test light connected to ground, probe each BCM power circuit. See WIRING DIAGRAMS  . If test light illuminates at all circuits, go to next step. If test light does not illuminate at all circuits, go to step 11).
  6. Using a test light connected to battery, probe each BCM ground circuit. See WIRING DIAGRAMS  . If test light illuminates at all circuits, go to next step. If test light does not illuminate at all circuits, go to step 12).
  7. Using DVOM, check for continuity between BCM 24-pin harness connector C1, terminal B9 (Brown/White wire) and Data Link Connector (DLC) terminal No. 2 (Brown/White wire). If continuity exists, go to next step. If continuity does not exist, go to step 10).
  8. Replace BCM. See BODY CONTROL MODULE (BCM)  under REMOVAL & INSTALLATION. Reprogram BCM. See PROGRAMMING  . Go to step 13).
  9. Repair open in ignition or battery feed to BCM fuse. If any fuse is open, locate and repair short in associated circuit. See WIRING DIAGRAMS  . Go to step 13).
  10. Locate and repair open in Brown/White wire between BCM connector C1 and DLC. Go to step 13).
  11. Locate and repair open in BCM power circuit. Go to step 13).
  12. Locate and repair open in BCM ground circuit. Go to next step.
  13. Turn ignition off. Reinstall all components or connectors. Clear DTCs. Ensure system is operating properly.
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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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