Emission Reduction Fluid Injector Quantity Test
Emission Reduction Fluid Injector Quantity Test
Diagnostic Instructions
* Perform the Diagnostic System Check - Vehicle Diagnostic System Check - Vehicle prior to using this diagnostic procedure.
* Review Strategy Based Diagnosis Strategy Based Diagnosis for an overview of the diagnostic approach.
* Diagnostic Procedure Instructions Diagnostic Procedure Instructions provides an overview of each diagnostic category.
Circuit/System Description
The selective catalytic reduction (SCR) system reduces oxides of nitrogen (NOx) emissions by injecting a metered amount of diesel exhaust fluid (DEF) or reductant into the exhaust gas stream entering the SCR catalyst. Within the SCR catalyst, the DEF reacts with the NOx to form nitrogen, carbon dioxide, and water vapor. Upstream and downstream NOx sensors provide the engine control module (ECM) with engine-out and tailpipe-out NOx levels. The ECM varies the amount of DEF added by varying the reductant injector duty-cycle in response to changes in engine-out NOx levels.
The ECM supplies voltage to the reductant injector on the injector high control circuit. The ECM turns ON the reductant injector by grounding the low control circuit of the injector.
Diagnostic Aids
It is common for DEF to crystallize over the nozzle of the reductant injector. The crystals will dissolve with use and the reductant injector will resume full functionality. The Reductant Quantity test may need to be performed multiple times to dissolve the crystallized DEF before diagnosing the reductant injector for performance issues.
Reference Information
Schematic Reference
Engine Controls Schematics [1][2]Electrical Diagrams
Connector End View Reference
Component Connector End Views 1-2 Shift Solenoid (SS) Valve (M30)
Description and Operation
Exhaust Aftertreatment System Description Exhaust Aftertreatment System Description
Electrical Information Reference
* Circuit Testing Circuit Testing
* Connector Repairs Connector Repairs
* Testing for Intermittent Conditions and Poor Connections Testing for Intermittent Conditions and Poor Connections
* Wiring Repairs Wiring Repairs
Scan Tool Reference
Control Module References Control Module References for scan tool information
Special Tools
J 45873 - Fuel Return Volume Test Kit
Circuit/System Testing
Warning
Diesel Exhaust Fluid (DEF) is corrosive. Do not allow it to come in contact with your skin, eyes, or the finished surfaces of the vehicle. If exposed, it may cause skin and eye irritation. Wear skin and eye protection when handling. Inhalation may cause irritation to the upper respiratory tract. Store in a cool, well-ventilated area. For more safety information, see the label of the Diesel Exhaust Fluid container. Failure to follow this procedure may result in injury and/or vehicle damage.
Note:
* Do not perform this diagnostic procedure unless you were sent here from another diagnostic procedure.
* Do not perform the Reductant Quantity Test if the diesel exhaust fluid (DEF) temperature is less than -7°C (19.5°F).
* The Reductant Quantity Test may need to be run multiple times to dissolve crystallized DEF and to restore proper flow pattern.
* The Reductant Quantity Test takes approximately 2 minutes to run.
* The engine control module will abort the Reductant Quantity Test after approximately 145 s.
1. Remove the Q61 Emission Reduction Fluid Injector from the exhaust leaving the reductant line connected.
2. Command the Reductant Quantity Test ON with a scan tool. While pointing the injector towards a shop towel or large container, observe the injector spray pattern. 3 individual streams and atomization or mist of DEF should be observed.
• If the function does not perform as specified
Inspect the Q61 Emission Reduction Fluid Injector lines for damage or restrictions or for being plugged.
• If a condition is found, repair as necessary
• If no condition is found, replace the Q61 emission reduction fluid injector
• If the function performs as specified
3. Position the Q61 Emission Reduction Fluid Injector nozzle towards one of the graduated scale container from the J 45873 - Fuel Return Volume Test Kit.
4. Command the Reductant Quantity Test ON with a scan tool. The injector should flow greater than 30 ml.
• If 30 ml or less
1. Disconnect the Q61 Emission Reduction Fluid Injector from the supply line.
2. Position the Q61 Emission Reduction Fluid Injector supply line towards the graduated scale container.
3. Command the Reductant Quantity Test ON with a scan tool. The supply line should flow greater than 30 ml.
• If 30 ml or less, test the Q61 emission reduction fluid injector and supply line for damage or restrictions.
• If greater than 30 ml, replace the Q 61 emission reduction fluid injector.
• If greater than 30 ml
5. All OK.
Repair Instructions
Perform the Diagnostic Repair Verification Verification Tests after completing the diagnostic procedure.
* Emission Reduction Fluid Injector Replacement Service and Repair
* Perform the scan tool Diesel Particulate Filter (DPF) Regeneration Enable Diesel Particulate Filter (DPF) Regeneration Enable procedure if the scan tool DPF Soot Mass is less than 30 g. If the scan tool DPF Soot Mass is greater than 30 g, perform the Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration procedure.