Cummins ISB CM850 (2003-06) Fault Code: FC0003 PID: SPN: FMI: Exhaust Gas Pressure Sensor Number 1 Circuit – Data Erratic, Intermittent, or Incorrect. The exhaust gas treatment monitor unit has detected that the exhaust gas pressure sensor number 1 is not changing.

Cummins ISB CM850 (2003-06) Fault Code: FC0003 PID: SPN: FMI: Exhaust Gas Pressure Sensor Number 1 Circuit – Data Erratic, Intermittent, or Incorrect. The exhaust gas treatment monitor unit has detected that the exhaust gas pressure sensor number 1 is not changing.

This fault code is activated when the exhaust gas treatment monitor unit detects that the exhaust gas pressure 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 pressure signal does not change during 30 minutes of engine operation where the exhaust gas temperature is above 250?C [482?F].

Possible causes:

1)Faulty exhaust gas pressure 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 three 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.