Cummins ISB CM850 (2003-06) Fault Code: FC0004 PID: SPN: FMI: Exhaust Gas Temperature Sensor Number 1 Circuit – Data Erratic, Intermittent, or Incorrect. The exhaust gas treatment monitor unit has detected that the exhaust gas temperature sensor number 1 is not changing.

Cummins ISB CM850 (2003-06) Fault Code: FC0004 PID: SPN: FMI: Exhaust Gas Temperature Sensor Number 1 Circuit – Data Erratic, Intermittent, or Incorrect. The exhaust gas treatment monitor unit has detected that the exhaust gas temperature sensor number 1 is not changing.

This fault code is activated when the exhaust gas treatment monitor unit detects that the exhaust gas temperature signal value is not changing (ie, stuck in range). In order for this fault code to activate, the exhaust gas treatment monitor unit must detect that the exhaust gas temperature is below 100?C [212?F] during one hour of continuous engine operation.

Possible causes:

1)Faulty exhaust gas temperature sensor.

This fault code will only be present in the exhaust gas treatment monitor unit, and will not be present in the engine electronic control module (ECM). The exhaust gas treatment fault code and maintenance lamps will both flash four times in sequence to alert the operator that this condition exists. The engine diagnostic lamps will not illuminate.

Possible repairs:

1)Replace the exhaust gas temperature sensor.