Cummins ISL CM850 (2003-06) Fault Code: 1667 PID: SPN: 3241 FMI: 2 Exhaust Gas Temperature 1 ? Data Erratic, Intermittent, or Incorrect. The exhaust gas temperature #1 sensor is not changing with engine operating conditions.

Cummins ISL CM850 (2003-06) Fault Code: 1667 PID: SPN: 3241 FMI: 2 Exhaust Gas Temperature 1 ? Data Erratic, Intermittent, or Incorrect. The exhaust gas temperature #1 sensor is not changing with engine operating conditions.

This diagnostic runs when the exhaust gas temperature sensors are compared to other engine temperatures during engine operation. The engine coolant temperature must be above 140?F before the diagnostic will run. If the value of the exhaust gas temperature #1 does not match the engine operating conditions, this fault code is logged.

Possible causes:

1)Stuck in-range exhaust gas temperature #1 sensor
2)High resistance in the exhaust gas temperature #1 sensor signal or return lines.

On-Board Diagnostics (OBD) Information:

1)The ECM illuminates the malfunction indicator lamp (MIL) on the second consecutive ignition cycle that 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 lamp and fault code can also be cleared using the INSITE? service tool.
3)The fault code will be cleared from memory after 40 consecutive drive cycles where the diagnostic runs and passes.

Possible repairs:

1)Replace the exhaust gas temperature #1 sensor.
2)Repair or replace the engine harness.
3)Replace the ECM.