Circuit DescriptionThe coolant temperature sensor is a variable resistor sensor and is used to measure the temperature of the coolant of the engine. The engine control module (ECM) supplies 5 volts to the coolant temperature signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the coolant temperature. Component LocationThe engine coolant temperature sensor is located on the thermostat housing. Conditions for Running the DiagnosticsThe engine must be turned OFF for period of 8 hours before this diagnostic will run. This diagnostic runs when the keyswitch is turned to the...

Circuit DescriptionThe exhaust gas recirculation (EGR) temperature sensor is a variable resistor sensor and is used to measure the temperature of the EGR gas flow after it exits the EGR cooler. The engine control module (ECM) supplies 5 volts to the EGR temperature signal circuit. The ECM monitors the change in voltage caused by changes in the resistance of the sensor to determine the EGR flow temperature. The EGR temperature value is used by the ECM for the engine protection system and engine emissions control. Component LocationThe EGR temperature sensor is located on the EGR connection tube between the EGR...

Circuit DescriptionThe 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...

Circuit DescriptionThe ECM calculates a differential pressure across the turbocharger using the intake manifold pressure sensor and the crankcase pressure sensor. Component LocationThe intake manifold pressure sensor is located in the air intake horn. The crankcase pressure sensor is mounted to the crankcase breather filter housing. Conditions for Running the DiagnosticsThis diagnostic runs continuously when the engine is running. Conditions for Setting the Fault CodesThe Engine Control Module (ECM) detected the calculated differential pressure across the turbocharger was greater than a threshold. Action Taken When the Fault Code is ActiveThe ECM illuminates the red STOP ENGINE lamp immediately after the...

Circuit DescriptionThe variable geometry turbocharger (VGT) is electronically activated by the VGT actuator. The VGT actuator is a smart device and receives information via the J1939 data link from the primary engine control module (ECM). The VGT actuator performs its own diagnostics and reports malfunctions back to the primary engine ECM, using the J1939 data link. The ECM then decodes the error message and converts it to a fault code. Component LocationThe VGT actuator is located on the turbocharger bearing housing. Conditions for Running the DiagnosticsThis diagnostic has to meet specific engine and aftertreatment conditions to run and complete. Conditions...