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Home >> Cadillac >> 1991 >> Seville Base >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - Tests W/Codes >> Diagnostic Tests >> BCM Code B556, Odometer EEPROM Error >> Replacement Procedure:
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Replacement Procedure:

  1. Remove instrument panel compartment door. Detach and move aside relay bracket assembly and fuse panel. With ignition off, disconnect BCM harness. Loosen BCM to bracket retaining nuts. Remove BCM.
  2. Remove 4 screws from EEPROM access cover. Remove cover. Using rocker type PROM remover, engage one end of carrier and press on vertical bar end of remover. Rock engaged end of EEPROM carrier up as far as possible. Engage opposite end of carrier and repeat process until EEPROM carrier is free of socket.
  3. Carefully install new EEPROM (mounted in carrier) into BCM socket while aligning small notch in carrier with small notch in socket. Press on EEPROM (carrier only) until EEPROM is firmly seated in socket. To complete installation, reverse removal procedure.
  4. Enter diagnostics and clear BCM code or codes. Start engine and observe odometer display. If ERROR continues to display and EEPROM is properly installed, replace BCM.
Fig 1: BCM Code B556, Schematic, Odometer EEPROM Error
G90F09296
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