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Programmable Read-Only Memory (Prom): Installation

  1. Ensure new PROM has same service number as old one. Place new PROM in PROM carrier. Position squarely over ECM PROM socket. Press on PROM carrier until PROM is firmly seated in ECM.
    NOTE: Ensure reference notches in both ECM and PROM are properly aligned. If PROM is installed backwards and key is turned on, PROM will be destroyed.
  2. Reinstall PROM access cover on ECM. Reinstall ECM in vehicle as previously described. Start engine and ground ALDL diagnostic test connector. Watch for trouble Code 51 or 52.
  3. If this occurs, PROM is not fully seated in ECM, 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.
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