Cummins ISB4.5 CM2150 Fault Code: 155 PID: 105 SPN: 105 FMI: 0 Intake Manifold 1 Temperature – Data Valid But Above Normal Operating Range – Most Severe Level.

Circuit Description
The intake manifold 1 temperature sensor is a variable resistor sensor and is used to measure the temperature of the air entering the intake manifold of the engine. The engine intake manifold temperature value is used by the engine control module (ECM) for the engine protection system and engine emission control. The ECM supplies 5 volts to the intake manifold temperature signal circuit, and monitors the change in voltage caused by changes in the resistance of the sensor to determine the intake manifold temperature. When the intake air is cold, the sensor (or thermistor) resistance is high. The ECM signal voltage only pulls down a small amount through the sensor to a ground. Therefore, the ECM senses a high signal voltage or low temperature. When the intake air is warm, the sensor resistance is low. The signal voltage pulls down a large amount. Therefore, the ECM senses a low signal voltage, or a high temperature.

Component Location
The engine intake manifold temperature sensor is located in the air intake manifold.

Conditions for Running the Diagnostics
This diagnostic runs continuously when the keyswitch is in the ON position.

Conditions for Setting the Fault Codes
The ECM detected the intake manifold air temperature was greater than the engine protection limit.

Action Taken When the Fault Code is Active
-The ECM illuminates the red STOP ENGINE lamp immediately when the diagnostic runs and fails.
-The torque output of the engine will be reduced.
-Maximum engine operating speed will be decreased.
-The engine will be shut off if the Engine Protection Shutdown feature is enabled

Conditions for Clearing the Fault Code
– To validate the repair, start the engine and let it idle for 1 minute.
-The fault code status displayed by the INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.
-The ECM will turn off the red STOP ENGINE lamp after the diagnostic runs and passes.
-The “Reset All Faults” command in the INSITE™ electronic service tool can be used to clear active and inactive fault codes.

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

Possible Causes
-Restricted air flow through the charge-air cooler
-Undersized charge-air cooler
-High turbocharger compressor outlet temperature.