Programmable Read Only Memory (Prom): Installation

Check that new PROM has same service number as the one being replaced. Place new PROM in PROM carrier in ECM. Position squarely over ECM PROM socket. Press on PROM carrier until PROM is firmly seated in ECM.
NOTE: Make sure that reference notch in both ECM and PROM are properly aligned. If PROM is installed backward and key is turned on, PROM will be destroyed.
Reinstall PROM access cover on ECM. Reinstall ECM in vehicle as previously described. Start engine and ground diagnostic test lead. Watch for trouble Code 51.
If Code 51 is stored, PROM is not fully seated in ECM, is installed backwards, has bent pins or is defective. If pins are bent and crack when straightened, PROM must be replaced. If PROM is installed backwards or is defective, it must be replaced.