PROM or Mem-Cal Replacement

If diagnostic procedures call for replacement of the ECM, first check that the installed PROM or MEM-CAL is the correct part. If it is correct, remove PROM or MEM-CAL from the defective ECM and install it in the new ECM, as the new ECM will not contain a PROM or MEM-CAL. When reconnecting power to the ECM, the ignition switch must be off to prevent internal ECM damage.