Pcm Code P051 - Prom Error
WARNING: This page is about a different car, the 1993 Cadillac Seville and 1993 Cadillac Eldorado. However, it is still accessible from the selected car via links, so may be relevant.
Ensure PROM is fully inserted in socket. If PROM is fully inserted, replace PROM, clear memory and recheck. If PCM Code P051 reappears, replace PCM.
See cautions under ELECTRONIC CONTROL MODULE (ECM) in I - SYS/COMP TESTS article in this section when replacing PROM or PCM.