Chellica

Interestingly, the part # matches for both BCMs: 16137944. I am in contact with Prospeedo about obtaining a new EEPROM.

I’m not sure if anything is wrong with the BCM itself or if it is just the PROM. In addition to the odometer error, the headlights don’t pop up automatically from the twilight sentinel and the warning chime that the fog lamps were left on after the key is pulled out doesn’t work. Would those indicate a bad BCM in addition to just the PROM? The cd player doesn’t work (I don’t think is related). Otherwise all other functions work (including headlights left on chime) and the car drives fine.

Hi guys I am also having the B556/bad EPROM odometer error. I tried swapping a working BCM from a 92 Olds Toronado which displayed mileage just fine prior to the swap to the Reatta (91), but it didn't work in the Reatta. I couldn't switch just the PROMS as they have different connections. I tried replacing the PCU, but that didn't fix the Odometer error. Does anyone know of any place that sells just the PROMS? Or any other ideas for a fix? I will also try calling around to different GM dealers, but I doubt any in my area (Minneapolis) are going to be able to reprogram them.