Cummins ISL CM850 (2003-06) Fault Code: 488 PID: 105 SPN: 105 FMI: 0 Intake Manifold 1 Temperature – Data Valid but Above Normal Operational Range – Moderately Severe Level. Intake manifold air temperature signal indicates intake manifold air temperature above engine protection warning limit.

The intake manifold air temperature sensor measures the temperature of the charge-air as it passes through the intake manifold.

Possible causes:

1)Plugged charge air cooler fins
2)Restricted airflow through the charge air cooler
3)Undersized charge air cooler
4)High turbocharger compressor outlet temperature.

Possible repairs:

1)Replace the intake manifold air temperature sensor.