Programmable Read-Only Memory (Prom): Installation

1. Ensure new PROM has same service number as old one. Position PROM squarely over ECM/PCM PROM access hole. Press on outer edges of PROM until PROM is firmly seated in ECM/PCM.
   NOTE: Ensure reference notches in both ECM/PCM and PROM are properly aligned. If PROM is installed backwards, PROM will be destroyed when ignition is turned on.
2. Install PROM access cover on ECM/PCM. Install ECM/PCM in vehicle. See ENGINE CONTROL MODULE (ECM)/POWERTRAIN CONTROL MODULE (PCM) . Start engine and enter self-diagnostics. See appropriate TESTS W/CODES article in this section. see the following list.
   • 4.6L, see: TESTS W/CODES - 4.6L .
   • 4.9L, see: TESTS W/CODES - 4.9L .

Check for trouble codes and code identification.

3) If code(s) sets, PROM is either not fully seated in ECM/PCM or installed backwards, has bent pins or is defective. If bent pins crack when trying to straighten, replace PROM. If PROM is installed backwards or is defective, replace PROM.