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DTC B1971: Inadvertent Power 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. Connect scan tool. Select DELAY INTERIOR LIGHTS from light test menu in SPECIAL FUNCTIONS. While observing scan tool, command DIL relay on and off by pressing on and off buttons on scan tool. If status changes with commanded state, go to next step. If status does not change with commanded state, go to step 4).
  3. Check for poor connection at BCM 32-pin connector C2 terminal C03 (Brown/Purple wire). Check all BCM power and ground circuits. See WIRING DIAGRAMS. Using scan tool, clear codes. Check for codes. If DTC B1971 is set, go to step 5). If DTC B1971 is not set, go to BCM SYSTEM CHECK  .
  4. Disconnect multifunction relay module connector. See Figure . Using DVOM, check resistance between multifunction relay module terminals No. 5 (Red wire) and No. 7 (Brown/Purple wire). If resistance is infinite, go to step 6). If resistance is not infinite, go to step 7).
  5. Replace BCM. See BODY CONTROL MODULE (BCM)  under REMOVAL & INSTALLATION. Reprogram BCM. See PROGRAMMING  . Perform BCM SYSTEM CHECK.
  6. Replace multifunction relay module. Perform BCM SYSTEM CHECK  .
  7. Disconnect BCM 32-pin connector C2. Using DVOM, check resistance between multifunction relay module terminal No. 7 (Brown/Purple wire) and BCM connector C2, terminal C03 (Brown/Purple wire). If resistance is less than 2 ohms, go to next step. If resistance is not less than 2 ohms, go to step 9).
  8. Move DVOM lead from multifunction relay module terminal No. 7 to ground. If resistance is infinite, go to step 10). If resistance is not infinite, go to step 11).
  9. Repair open in Brown/Purple wire between BCM and multifunction relay module. Perform BCM SYSTEM CHECK  .
  10. Leave DVOM connected as specified in step 8). Switch DVOM to DC volts scale. Record voltage reading. Turn ignition switch to ON position. Record voltage reading. If both voltage readings are less than one volt, go to step 3). If both voltage readings are not less than one volt, go to step 12).
  11. Repair short to ground in Brown/Purple wire between BCM and multifunction relay module. Perform BCM SYSTEM CHECK  .
  12. Repair short to battery in Brown/Purple wire between BCM and multifunction relay module. Perform BCM SYSTEM CHECK  .
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