Paccar

Reason:Transmission Output Shaft Speed – Abnormal Update Rate. No communication or an invalid data transfer rate has been detected on the J1939 data link between the ECM and the transmission output shaft speed sensor. Effect:None on performance Circuit Description:Normally, switches, accelerators, and other components are connected to the engine control module (ECM) directly through individual wires. Multiplexing allows those same components to be hard wired to an original equipment manufacturer (OEM) vehicle electronic control unit (VECU) or transmission electronic control unit (ECU) in the cab. Then component values and states from components such as sensors, accelerators, and switches can be...

Reason:Engine Coolant Temperature – Data Erratic Intermittent or Incorrect. The engine coolant temperature sensor is reading an erratic value at initial key ON. Effect:None on performance. Circuit Description:The 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 Location:The engine coolant temperature sensor is located on the thermostat housing. Conditions for Running the...

Reason:Engine Air Filter Differential Pressure – Data Valid But Above Normal Operating Range – Moderately Severe Level Effect:Possible reduced engine performance. Circuit Description:The Engine Control Module (ECM) calculates the restriction across the air filter using sensors within the air management system. Component Location:Not Applicable Conditions for Running the Diagnostics:This diagnostic runs continuously when the engine is running. Conditions for Setting the Fault Codes:The Engine Control Module (ECM) detected the compressor intake air restriction is above a calibratible value. Action Taken When the Fault Code is Active:1) The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and...

Reason:Engine Air Filter Differential Pressure – Data Valid But Above Normal Operating Range – Moderately Severe Level Effect:Possible reduced engine performance. Circuit Description:The Engine Control Module (ECM) calculates the restriction across the air filter using sensors within the air management system. Component Location:Not Applicable Conditions for Running the Diagnostics:This diagnostic runs continuously when the engine is running. Conditions for Setting the Fault Codes:The Engine Control Module (ECM) detected the compressor intake air restriction is above a calibratible value. Action Taken When the Fault Code is Active:1) The ECM illuminates the amber CHECK ENGINE lamp immediately when the diagnostic runs and...

Reason:Aftertreatment Diesel Particulate Filter Regeneration too Frequent – Condition Exists. The system has detected the need for an active regeneration has occurred too soon following the last active regeneration. Effect:None on performance. Circuit Description:The ECM records the time from the completion of an active regeneration of the aftertreatment diesel particulate filter until the ECM request another active regeneration of the diesel particulate filter. Component Location:The aftertreatment diesel particulate filter is located in the exhaust system and is installed by the original equipment manufacturer (OEM). Refer to the OEM service manual. Conditions for Running the Diagnostics:This diagnostic only runs after successful...