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