DTC B556: Odometer Ee Prom Error: Description
WARNING: This page is about a different car, the 1988 Cadillac Allante and 1987 Cadillac Allante. However, it is still accessible from the selected car via links, so may be relevant.
Code B556 indicates that the EE PROM, which records elapsed odometer mileage, is not being read by the BCM. Usually along with Code B556, "ERROR" will be displayed in the odometer display.
- Check for proper EE PROM installation.
- If PROM is properly installed with no bent pins, then replace the EE PROM.
- If a properly installed EE PROM continues to display "ERROR", replace the BCM.
NOTE:
A new EEPROM will have to be adjusted to the current mileage and proper VIN and option content by a GM dealer or Delco repair station.