The BMW labour op codes (FRU codes) are looked up as follows:
- The chassis number (last 7 of the VIN) are found in the BM.chass table. This gives a sales model code and a production month/year
- The sales model code is looked up in the BM.engty table to get a service model code
- Using the service model code and the production month/year the BM.rtsco & BM.rtstm tables are looked up to get the FRU code, its description, and the time.