Fault Memory
Both the FICU and ICU store faults for self-diagnosis. If a fault occurs, the computer memory will store a code and corrective action will take place. For example: the coolant temperature sensor develops an open circuit. In this case, both control units will assume a calculation value of a fully warmed engine.
The fault will be displayed by a flashing of the engine control indicator light. By inserting a fuse into the top of the fuel relay for 4 seconds, the diagnostic terminals will be grounded and the memories will be displayed by a flashing sequential code on the instrument cluster.
If the ignition system is operating in a fully retarded position because of engine knock or a problem has developed in the knock sensor system the indicator light will flash while driving.