Cummins ISB CM850 (2003-06) Fault Code: 1681 PID: SPN: 3361 FMI: 12 Catalyst Dosing Control Unit ? Bad Intelligent Device or Component. An internal error has been detected in the catalyst dosing control unit. Fault code 1681 is triggered when the Dosing Control Unit has detected an internal error. The only troubleshooting that can be done is to recalibrate the engine ECM. If fault code 1681 is still active after the engine ECM has been recalibrated, the Dosing Control Unit will need to be replaced. On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines): 1)The ECM illuminates the malfunction indicator lamp...

Cummins ISB CM850 (2003-06) Fault Code: 1682 PID: SPN: 3362 FMI: 11 Aftertreatment Diesel Exhaust Fluid Dosing Unit Input Lines – Condition Exists. An error has been detected by the catalyst dosing control unit. The diesel exhaust fluid dosing unit process consists of three phases, which occur in the following sequence: priming, dosing, and purging. Priming: 1)The diesel exhaust fluid dosing unit will attempt to prime every 30 seconds for 20 attempts. The attempts can be counted by listening for the air solenoid to click every 30 seconds.2)The diesel exhaust fluid dosing unit can take up to 12 minutes to...

Cummins ISB CM850 (2003-06) Fault Code: 1683 PID: SPN: 3449 FMI: 3 Catalyst Tank Heater Circuit ? Voltage Above Normal, or Shorted to High Source. High signal voltage detected at the catalyst tank heater relay sensor circuit. This fault code cannot detect any circuit failures on the heater side of the relay. Only circuit errors between the ECM and the relay can be detected by this fault code. Possible causes: 1)Catalyst tank heater relay signal wire not connected to the relay2)Catalyst tank heater relay return wire not connected to the relay3)Faulty catalyst tank heater relay4)Open circuit in the catalyst tank...

Cummins ISB CM850 (2003-06) Fault Code: 1684 PID: SPN: 3363 FMI: 4 Catalyst Tank Heater Circuit ? Voltage Below Normal, or Shorted to Low Source. Low signal voltage detected at the catalyst tank heater relay sensor circuit. This fault code cannot detect any circuit failures on the heater side of the relay. Only circuit errors between the ECM and the relay can be detected by this fault code. Possible causes: 1)A shorted catalyst tank heater relay2)Catalyst tank heater signal wire shorted to ground. On-Board Diagnostics (OBD) Information (Euro 4 Certified Engines): 1)The ECM illuminates the malfunction indicator lamp (MIL) when...

Cummins ISB CM850 (2003-06) Fault Code: 1687 PID: SPN: 3050 FMI: 0 Catalyst Over Temperature – Data Valid but Above Normal Operational Range – Most Severe Level. Very high temperatures have been detected in the aftertreatment system. This fault is triggered when the temperature at the catalyst exhaust outlet exceeds the maximum allowable temperature for a given engine rating. On-Board Diagnostic (OBD) Information: 1)The ECM illuminates the malfunction indicator lamp (MIL) when the diagnostic runs and fails.2)The ECM turns OFF the malfunction indicator lamp (MIL) after 3 consecutive ignition cycles that the diagnostic runs and does not fail. The MIL...