Programmable Read Only Memory (Prom)(Except 2.5L): Installation
- Check that new PROM has same service number as the one being replaced. Place new PROM and carrier in ECM. Press on PROM carrier until PROM is firmly seated in ECM. Make sure that reference notch in ECM and PROM are properly aligned with small notch and (1). See Fig 1 .
- Install PROM access cover on ECM and install ECM in vehicle. Start engine and ground diagnostic test lead. Code 12 should flash at least 4 times, with no other codes stored. This confirms proper PROM installation.
- If Code 51 is stored, or if "SERVICE ENGINE SOON" light stays on constantly with no codes, 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.