Group 28 Engine Control Module (ECM) Diagnostic Trouble Codes (DTCs) ECM SPN 975, Estimated Percent Fan Speed – (MID 128 PID 26) 45 FMI 5 • Current below normal or open circuit • Open circuit • Yellow electronic malfunction lamp illuminated • Fautly intake air heater (IAH) 2 Type of fault: FMI Description: Fault Condition: Possible Symptoms: Possible Cause:
FMI 3 • Voltage above normal, or shorted to high source • Missing signal from Fan Speed Sensor • Short Circuit +, Measuring line • Short Circuit -, Measuring line • Open Circuit, Measuring line • Open Circuit, Ground line • Higher fuel consumption • Will work as on/off fan, 100%fan speed if cooling is needed • Cooling Fan Speed (CFS) sensor failure • Faulty Cooling Fan Speed (CFS) sensor harness