1998 Johnson Evinrude "EC" 150, 175 FFI Service Manual, P/N 520211, Page 48Get this manual
12-Volt Circuit Sensormonitors rectifierregulator 12-volt outputThis is the circuit that supplies all 12-volt componentcircuit requirementsIf voltage is out of limits, high or low, the ECU will store service code and turn on the "CHECK ENGINE" lightROM Verificationis continual ECU self-test of factory programmingThe ECU will turn on the "CHECK ENGINE" light and store service code if, at any time, program failure is detectedExternal ECU Sensors