16 Internal Controller (ROM Check Failure)

WHEN MONITORED:
After a reset (ignition key turned to the RUN position or after cranking engine).

SET CONDITION:
ROM check sum does not match a known constant.

SET TIME:
Less than 1 second when the above conditions are met.

EFFECT:
Transmission enters limp-in mode.

THEORY OF OPERATION:
When the controller is reset, the microprocessor checks the integrity of the program memory (ROM). It adds all used bytes in the program memory. The amount should be the same as a known constant (stored in program memory).

PROBABLE CAUSES:
Internal controller failure.