DTC B2805: RFA Programming/Diagnostic Mode Message Not Received: Testing

1998 Buick Regal 25th Anniversary EditionSECTION Testing
  1. If BCM diagnostic system check was performed, go to next step. If BCM diagnostic system check was not performed, go to BCM DIAGNOSTIC SYSTEM CHECK  .
  2. Turn ignition switch to LOCK position. Attempt to enable transmitter programming/diagnostic mode. See KEYLESS ENTRY SYSTEM - REMOTE article. If transmitter programming/diagnostic mode can be entered, go to next step. If transmitter programming/diagnostic mode cannot be entered, go to step 4).
  3. Exit transmitter programming/diagnostic mode by turning ignition switch to RUN position. Using scan tool, clear DTCs. Turn ignition switch to LOCK position. Enable transmitter programming/diagnostic mode again. Check for DTCs. If DTC B2805 is set, go to step 6). If DTC B2805 is not set, go to step 8).
  4. Using keyless entry transmitter, attempt to lock and unlock doors. If doors lock and unlock, go to step 9). If doors do not lock and unlock, go to next step.
  5. Using Device Control function on Tech 2 scan tool, activate RFA link output. Using DVOM, check voltage between BCM Pink 32-pin connector C1, terminal C15 (Black wire) and ground. If reading is less than 2 volts, go to step 7). If reading is not less than 2 volts, go to next step.
  6. Replace BCM. See REMOVAL & INSTALLATION  . Reprogram BCM. See procedures in BCM PROGRAMMING  . Go to step 9).
  7. Check for poor connections at RCDLR. If connections are okay, replace RCDLR. Go to step 9).
  8. System is operating properly at this time. See DIAGNOSTIC AIDS. After any repairs are made, go to next step.
  9. Turn ignition switch to LOCK position. Reinstall all components and connectors. Turn ignition switch to RUN position. Using scan tool, clear DTCs. Check for DTCs. If any DTCs are current, perform BCM DIAGNOSTIC SYSTEM CHECK  . If no DTCs are current, 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.