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Reason:Aftertreatment Diesel Exhaust Fluid Pressure Sensor – Data Valid But Above Normal Operating Range – Moderately Severe Level. The diesel exhaust fluid dosing unit has detected a blockage in the diesel exhaust fluid return flow. Effect:Possible reduced engine performance Circuit Description:The Engine Control Module (ECM) provides a 5 volt supply and a ground to the aftertreatment diesel exhaust fluid pressure sensor. The pressure sensor provides a signal to the ECM on the sensor signal circuit. This sensor signal voltage changes, based on the aftertreatment diesel exhaust fluid pressure supplied by the dosing unit. The ECM will detect a low signal...

Reason:Aftertreatment Diesel Exhaust Fluid Pressure Sensor – Data Valid But Above Normal Operating Range – Moderately Severe Level. The diesel exhaust fluid dosing unit has detected a blockage in the diesel exhaust fluid return flow. Effect:Possible reduced engine performance Circuit Description:The Engine Control Module (ECM) provides a 5 volt supply and a ground to the aftertreatment diesel exhaust fluid pressure sensor. The pressure sensor provides a signal to the ECM on the sensor signal circuit. This sensor signal voltage changes, based on the aftertreatment diesel exhaust fluid pressure supplied by the dosing unit. The ECM will detect a low signal...

Reason:Aftertreatment Diesel Exhaust Fluid Return Valve – Voltage Above Normal or Shorted to High Source. High signal voltage detected at the aftertreatment diesel exhaust fluid return valve. Effect:Possible reduced engine performance Circuit Description:The aftertreatment diesel exhaust fluid return valve is controlled by the Engine Control Module (ECM). The return valve position determines where diesel exhaust fluid will flow as it exits the dosing unit. When the return valve is activated, the dosing system will purge and return the diesel exhaust fluid in the lines to the tank. Component Location:The aftertreatment diesel exhaust fluid return valve is internal to the aftertreatment...

Reason:Aftertreatment Diesel Exhaust Fluid Return Valve – Voltage Below Normal, or Shorted to Low Source. Low signal voltage detected at the diesel exhaust fluid return valve. Effect:Possible reduced engine performance. Circuit Description:The aftertreatment diesel exhaust fluid return valve is controlled by the Engine Control Module (ECM). The return valve position determines where diesel exhaust fluid will flow as it exits the dosing unit. When the return valve is activated, the dosing system will purge and return the diesel exhaust fluid in the lines to the tank. Component Location:The aftertreatment diesel exhaust fluid return valve is internal to the aftertreatment diesel...

Reason:Aftertreatment SCR Catalyst Conversion Efficiency – Data Valid But Below Normal Operating Range – Moderately Severe Level. NOx conversion across the SCR catalyst is too low. Effect:Possible reduced engine performance. Circuit Description:The engine control module (ECM) monitors the NOx concentration in the engine’s exhaust gases using an aftertreatment intake NOx sensor and an aftertreatment outlet NOx sensor. By comparing these two values, the ECM is able to determine the conversion efficiency of the SCR catalyst and dosing system. Component Location:The SCR catalyst is located in the vehicle’s exhaust system, after the diesel particulate filter and decomposition tube. Conditions for Running...