Cummins ISB CM850 (2003-06) Fault Code: 1668 PID: SPN: 1761 FMI: 4 Catalyst Tank Level Sensor Circuit ? Voltage Below Normal, or Shorted to Low Source. Low signal voltage detected at the catalyst tank level sensor circuit. The catalyst tank level sensor shares supply and return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active. Before troubleshooting Fault Code 1668, check for multiple faults. Possible causes: 1)Signal circuit open or shorted to ground in the engine harness or sensor2)Supply line open or shorted to ground. On-Board...

Cummins ISB CM850 (2003-06) Fault Code: 1669 PID: SPN: 1761 FMI: 3 Catalyst Tank Level Sensor Circuit ? Voltage Above Normal, or Shorted to High Source. High signal voltage detected at the catalyst tank level sensor circuit. The catalyst tank level sensor shares supply and return wires in the engine harness with other sensors. Opens and shorts in the engine harness can cause multiple fault codes to be active. Before troubleshooting Fault Code 1669, check for multiple faults. Possible causes: 1)Open return circuit in the harness, connectors, or sensor2)Signal circuit shorted to sensor supply or battery voltage. On-Board Diagnostics (OBD)...

Cummins ISB CM850 (2003-06) Fault Code: 1671 PID: SPN: 1761 FMI: 1 Catalyst Tank Level ? Data Valid but Below Normal Operational Range ? Moderately Severe Level. Low catalyst solution level has been detected in the catalyst solution tank. Fault code 1671 is triggered when low catalyst solution level has been detected in the catalyst solution tank. Add catalyst solution to the tank. This fault code is only a warning for low catalyst tank solution level. On-Board Diagnostic (OBD) Information: 1)The ECM illuminates the appropriate amber or red fault lamp when the diagnostic runs and fails.2)The ECM turns off the...

Cummins ISB CM850 (2003-06) Fault Code: 1673 PID: SPN: 1761 FMI: 1 Catalyst Tank Level ? Data Valid but Below Normal Operational Range ? Most Severe Level. No catalyst solution has been detected in the catalyst solution tank. Fault code 1673 is triggered when the catalyst solution level sensor has detected that the catalyst tank is empty. Catalyst solution may still be visible inside the tank when this fault code is active. Add catalyst solution to the tank. On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines): 1)The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.2)The...

Cummins ISB CM850 (2003-06) Fault Code: 1674 PID: SPN: 3249 FMI: 4 Exhaust Gas Temperature 2 Circuit ? Voltage Below Normal, or Shorted to Low Source. Low signal voltage detected at the catalyst exhaust temperature sensor circuit. The catalyst outlet temperature sensor shares return wires in the engine harness with other sensors. A shorted return can cause multiple fault codes to be active. Possible causes: 1)Signal shorted to ground in the harness2)Signal shorted to return or ground in the sensor. On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines): 1)The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs...