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 Emission Control Systems
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
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.
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 reduction fluid injector lines for restrictions or for being plugged. If the reduction fluid injector lines test normal, replace the Q61 emission reduction fluid injector.
3. Position the Q61 emission reduction fluid injector nozzle towards one of the graduated scale container from the J 45873.
4. Command the Reductant Quantity Test ON with a scan tool. The injector should flow greater than 30 ml.
• If less than the specified value, test the Q61 emission reduction fluid injector and supply line for damage or restrictions. If the lines test normal, replace the Q61 emission reduction fluid injector.
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.