Cummins ISB4.5 CM2150 Fault Code: 2964 PID: 105 SPN: 105 FMI: 0 Intake Manifold 1 Temperature – Data Valid But Above Normal Operating Range – Least 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 electronic control module (ECM) supplies 5 volts to the intake manifold temperature signal circuit. The ECM 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.

This fault code indicates that the intake manifold temperature has exceeded the maximum engine protection limit.

Component Location
The intake manifold 1 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 or when the engine is running.

Conditions for Setting the Fault Codes
The ECM detects that the intake manifold temperature is greater than a calibratible limit set in the ECM.

Action Taken When the Fault Code is Active
-The ECM illuminates the amber CHECK ENGINE light immediately when the diagnostic runs and fails.
-The torque output of the engine will be reduced.

Conditions for Clearing the Fault Code
The maximum torque output of the engine will return and the fault code will go inactive after the intake manifold temperature drops below a calibratible limit set in the ECM.

The ECM will turn off the amber CHECK ENGINE light and the fault code will go inactive immediately after the diagnostic runs and passes.

Shop Talk
The intake manifold 1 temperature sensor measures the temperature of the charge-air as it passes through the intake manifold.

Possible Causes
-Plugged charge air cooler fins
-Restricted airflow through the charge air cooler
-An undersized charge air cooler
-High turbocharger compressor outlet temperature.