Circuit DescriptionThe Engine Control Module (ECM) provides 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 LocationThe intake manifold 1 pressure/temperature sensor is located in the air intake horn.

Conditions for Running the DiagnosticsThis diagnostic runs continuously when the keyswitch is in the ON position or when the engine is running.

Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the intake manifold temperature was greater than 120°C [248°F].

Action Taken When the Fault Code is ActiveThe ECM logs the fault code immediately when the diagnostic runs and fails.The torque output of the engine will be reduced.Conditions for Clearing the Fault CodeTo validate the repair using a Diagnostic Road Test, utilize a route that incorporates both stop and go city type driving and steady state highway type driving. It may be necessary to load the unit for certain diagnostics in the ECM to run.To validate the repair using a Chassis Dynamometer, utilize a routine that incorporates acceleration and motoring events, steady state highway type operation, and load. This will simulate normal driving and allow the diagnostics in the ECM to run.The fault code status displayed by INSITE™ electronic service tool will change to INACTIVE immediately after the diagnostic runs and passes.The Reset All Faults command in INSITE™ electronic service tool can be used to clear active and inactive faults, as well as extinguish the MIL for OBD applications.

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

Possible causes of this fault code include:

Plugged charge-air cooler finsRestricted airflow through the charge-air coolerAn undersized charge-air coolerHigh turbocharger compressor outlet temperature.

Possible Cause:1) Intake Manifold temperature sensor failure2) ECM calibration