P202E
DTC P202E
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.
DTC Descriptors
DTC P202E
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Reductant Injector Performance
Diagnostic Fault Information
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.
Conditions for Running the DTCs
P202E
* DTCs P1048, P1049, P2047, P2048, or P2049 are not set
* SCR reductant level not in restriction or empty level state
* The engine speed is greater than 600 RPM.
* The battery voltage is greater than 11 V.
* The ambient air and emission reduction fluid tank temperatures are warmer than -7°C (19°F).
* The engine run time is greater than 10 s.
* The calculated reductant injector temperature is between -7 to +100°C (19-212°F).
* The reductant pressure is between 350-650 kPa (51-94 psi).
* The DTC runs continuously once the above conditions are met.
Conditions for Setting the DTC
The ECM detects that the commanded state of the driver and the actual state of the control circuit do not match for 90 injections.
Action Taken When the DTC Sets
DTCs P202E is a Type A DTC.
The ECM inhibits the reductant system when DTC P202E is set.
Conditions for Clearing the DTC
DTCs P202E, is a Type A DTC.
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
* Diesel Exhaust Fluid (DEF) Warning Strategy (DEF Quality) Diesel Exhaust Fluid (DEF) Warning Strategy (DEF Quality)Diesel Exhaust Fluid (DEF) Warning Strategy (DEF Level) Diesel Exhaust Fluid (DEF) Warning Strategy (DEF Level)Diesel Exhaust Fluid (DEF) Warning Strategy (Emission Control) Diesel Exhaust Fluid (DEF) Warning Strategy (Emission Control)Diesel Exhaust Fluid (DEF) Warning Strategy (Anti-Tampering) Diesel Exhaust Fluid (DEF) Warning Strategy (Anti-Tampering)
* 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
DTC Type Reference
Powertrain Diagnostic Trouble Code (DTC) Type Definitions Powertrain Diagnostic Trouble Code (DTC) Type Definitions
Scan Tool Reference
Control Module References Control Module References for scan tool information
Circuit/System Verification
1. Ignition ON, observe the DTC information with a scan tool. DTC P1043, P1044, P204B, P204C, P204D, P208A, P208B, P208C, or P208D should not be set.
• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.
Warning
Road test a vehicle under safe conditions and while obeying all traffic laws. Do not attempt any maneuvers that could jeopardize vehicle control. Failure to adhere to these precautions could lead to serious personal injury and vehicle damage.
Note:
This DTC may set after a DPF Service Regeneration. The excessive exhaust temperatures created during a DPF Service Regeneration causes the diesel exhaust fluid (DEF) to crystalize. The crystalize DEF will cause the Q61 emission reduction fluid injector to stick. Idling the engine for 10 minutes will cause the DEF to liquify and un-stick the injector.
2. Engine idling at operating temperature for 10 minutes. Road test until the scan tool EGT Sensor 2 parameter is greater than 180°C (356°F). Observe the DTC information with a scan tool. DTC P202E should not set.
3. Operate the vehicle within the Conditions for Running the DTC to verify the DTC does not reset. You may also operate the vehicle within the conditions that you observed from the Freeze Frame/Failure Records data.
Circuit/System Testing
1. Ignition OFF, remove the Q61 emission reduction fluid injector from the exhaust pipe leaving the reductant line and electrical connector connected.
2. Place the Q61 emission reduction fluid injector into a suitable container.
3. Ignition ON, command the Reductant System Leak Test ON with a scan tool. Allow the pressure to build for at least 2 minutes. The first 60 s, the system performs a system purge. Observe the scan tool Reductant Pressure sensor parameter. The reading should be between 400-650 kPa (58-94 psi). The Q61 emission reduction fluid injector should not leak.
• If a condition is found, replace the Q61 emission reduction fluid injector.
4. Perform the Emission Reduction Fluid Injector Quantity Test Emission Reduction Fluid Injector Quantity Test. The Q61 emission reduction fluid injector should pass the test.
• If the injector fails the test, replace the Q61 emission reduction fluid injector.
Repair Instructions
* Emission Reduction Fluid Injector Replacement Service and Repair
* Perform the scan tool Reductant Injector Reset procedure after replacing the Q61 emission reduction fluid injector.
Repair Verification
1. Install any components or connectors that have been removed or replaced during diagnosis.
2. Perform any adjustment, programming, or setup procedures that are required when a component or module is removed or replaced.
3. Clear the DTCs.
4. Ignition OFF, all vehicle systems OFF, this may take up to 2 minutes.
5. Ignition ON, perform the Reductant System Data Reset with a scan tool in order to clear the DEF lamp.
• If the DEF lamp does not turn OFF, a condition with the system still exists.