P20EE
DTC P20EE, P249D, P249E, or P2BAD
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 provide an overview of each diagnostic category.
DTC Descriptors
DTC P20EE
- NOx Catalyst Efficiency Below Threshold
DTC P249D
- Closed Loop Reductant Injection Control At Limit - Flow Too Low
DTC P249E
- Closed Loop Reductant Injection Control At Limit - Flow Too High
DTC P2BAD
- Exhaust NOx Concentration High-Unknown Reason
Diagnostic Fault Information
Circuit/System Description
The selective catalytic reduction system reduces oxides of nitrogen (NOx) emissions by injecting a metered amount of diesel exhaust fluid or reductant into the exhaust gas stream entering the diesel particulate filter (DPF). Within the selective catalytic reduction catalyst, the reductant 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 uses the 2 NOx sensors to control exhaust NOx levels. The NOx sensor measures the amount of NOx and oxygen in the exhaust system. The first NOx sensor is located at the outlet of the turbocharger and monitors the engine out NOx. The second NOx sensor is located in the DPF that monitors NOx levels exiting the DPF. The ECM varies the amount of reductant added by varying the reductant injector duty cycle in response to changes in engine exhaust out NOx levels.
Conditions for Running the DTCs
* The BARO pressure is greater than 75 kPa (11 psi).
* The ambient air and reductant temperatures are warmer than -7°C (+19°F) and the reductant tank is not in frozen tank status.
* The engine speed is between 1,000-3,000 RPM.
* The average selective catalytic reduction temperature is between 240-290°C (464-564°F).
* The emission reduction fluid tank level is above 33%.
* The battery voltage is greater than 11 V for greater than 3 s.
* The engine run time is greater than 10 s.
* Vehicle is not in a DPF regeneration.
* Engine ON time must be less than 25 minutes.
* The DTCs run once per drive cycle when the above conditions are met.
Conditions for Setting the DTC
The ECM has determined the catalyst efficiency has degraded below a calibrated threshold.
Action Taken When the DTC Sets
* DTC P20EE and P2BAD are Type A DTCs.
* DTCs P249D and P249E are Type B DTCs.
Conditions for Clearing the DTC
* DTC P20EE and P2BAD are Type A DTCs.
* DTCs P249D and P249E are Type B DTCs.
Diagnostic Aids
* Using fuel other than ultra low sulfur content fuel will cause this DTC to set.
* A quality message may be present on the driver information center (DIC) with or without DTCs P20EE or P2BAD.
* A leak in the reductant system can be located by inspecting for a build-up of crystallized diesel exhaust fluid.
* Water in the reductant tank will cause this DTC to set. Multiple Reductant Fluid Quality tests will be necessary to heal the system once the reductant is replaced with fresh reductant.
* It is recommended that the following parameters are recorded every 2 minutes during and after each Reductant Fluid Quality Test and DPF Service Regeneration for reference as they may become necessary:
- NOx Sensor 1 NOx Concentration
- NOx Sensor 2 NOx Concentration
- EGT Sensor 1
- EGT Sensor 2
- EGT Sensor 3
- EGT Sensor 4
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 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
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.
2. Verify DTCs P0101, P0400, P0401, P0402, P0420, P1043, P1044, P1048, P1049, P11CB, P11CC, P11DB, P11DC, P140B, P140C, P202E, P2047, P2048, P2049, P204B, P204C, P204D, P204F, P205B, P205C, P025D, P208A, P208B, P208D, P20A0, P20A2, P20A3, P20E8, P20E9, P2200, P2201, P2202, P2203, P2205, P2209, P229E, P229F, P22A0, P22A1, P22A3, P22A7, P2413, PC29D, or PC29E are not set.
• If any of the DTCs are set
Refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle.
• If none of the DTCs are set
3. Verify none of the conditions listed below do not exist with the diesel oxidizing catalyst or NOx sensors, selective catalytic reduction system and DPF:
* Physical damage or alterations
* Internal rattles caused by a damaged catalyst substrate
* Exhaust system leaks-Refer to Exhaust Leakage Testing and Inspection.
* Loose B195 NOx sensors or B131 Exhaust Gas Temperature Sensors-Refer to DTC P229F P229F.
• If a condition is exists
Repair as necessary.
• If no condition exists
4. Verify the reductant is not contaminated. Refer to Contaminants-in-Diesel Exhaust Fluid Diagnosis Contaminants-in-Diesel Exhaust Fluid Diagnosis.
• If contaminated
Repair as necessary.
• If not contaminated
5. Ignition ON.
6. 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.
7. Verify there are no leaks in the reductant lines.
• If a condition is found
Repair as necessary.
• If no condition is found
8. Verify the scan tool Reductant Pressure sensor parameter is between 400-650 kPa (58-94 psi).
• If not between 400-650 kPa (58-94 psi)
Refer to DTC P208B P208B.
• If between 400-650 kPa (58-94 psi)
9. Remove the Q61 Emission Reduction Fluid Injector from the exhaust pipe leaving the reductant line and electrical connector connected. Place the injector into a suitable container.
10. Verify the Emission Reduction Fluid Injector Quantity Test Emission Reduction Fluid Injector Quantity Test passes when commanded ON with a scan tool.
• If the test does not pass
1. Disconnect the Q61 Emission Reduction Fluid Injector from the supply line.
2. Verify at least 30 mL of DEF flows from the supply line at the injector connection when commanding the Emission Reduction Fluid Injector Quantity Test Emission Reduction Fluid Injector Quantity Test ON with a scan tool.
• If greater than 30 mL , replace the Q61 Emission Reduction Fluid Injector.
• If less than 30 mL, inspect the reductant lines for kinks or restrictions and repair as necessary then verify 30 mL is present while performing the Quantity Test with the injector connected.
• If the test passes
11. Verify none of the conditions listed below exist:
* Leaking Q57 Indirect fuel injector-Refer to Exhaust Aftertreatment Fuel Injector Diagnosis Testing and Inspection.
* Leaking fuel injectors-Refer to Fuel Injector Balance Test with Tech 2 Fuel Injector Balance Test with Tech 2.
* Engine oil consumption-Refer to Oil Consumption Diagnosis Oil Consumption Diagnosis.
* Engine coolant consumption-Refer to Coolant in Combustion Chamber Coolant in Combustion Chamber.
* Engine mechanical condition-Refer to Symptoms - Engine Mechanical Symptoms - Engine Mechanical.
• If a condition exists
Repair as necessary.
• If no condition exists
Note: The reductant fluid quality test may need to be performed 3 times to complete step 12.
12. Verify the Reductant Fluid Quality Test (With or without DTCs) Component Tests and General Diagnostics passes when commanded ON with a scan tool.
• If the first test failed
1. Perform the Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration with a scan tool while performing the Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration with a scan tool.
2. Verify the scan tool EGT Sensor 3 and EGT Sensor 4 is between 450-700°C (842-1292°F).
• If less than 450°C (842°F) or greater than 700°C (1292°F), verify the conditions listed below do not exist and repair as necessary:
* Intake system leaks-Refer to Charge Air Cooler Diagnosis (Full System Air Leak Test) Charge Air Cooler Diagnosis (Full System Air Leak Test)Charge Air Cooler Diagnosis (Induction System Smoke Test) Charge Air Cooler Diagnosis (Induction System Smoke Test).
* Poor fuel quality-Refer to Contaminants-in-Fuel Diagnosis Contaminants-in-Fuel Diagnosis.
* High sulfur content fuel
• If between 450-700°C (842-1292°F)
Note: The EGT temperatures should be stabilize during the service regeneration.
3. Verify the scan tool EGT 2 temperature is greater than both of the EGT 3 and EGT 4.
• If EGT 2 temperature is less than either of the EGT 3 and EGT 4 temperatures, replace the DOC.
• If EGT 2 temperature is greater than both the EGT 3 and EGT 4
4. Idle engine for 15 min.
5. Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down.
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: Do not turn the ignition off prior to performing the following Reductant Fluid Quality Test.
6. Drive the vehicle for 25 min.
7. Repeat the Reductant Fluid Quality Test in step 12.
• If the second test failed
Ignition OFF and all vehicle systems OFF. It may take up to 2 minutes for all vehicle systems to power down. Immediately following the key cycle, repeat the Reductant Fluid Quality Test in step 12, for a third time.
• If the third test failed
1. Drive the vehicle and perform a heavy acceleration followed by a zero throttle deceleration.
2. Verify the scan tool parameters listed below return to less than 5 ppm.
* NOx Sensor 1 NOx Concentration
* NOx Sensor 2 NOx Concentration
• If 5 ppm or greater, replace the appropriate B195 Nitrogen Oxide Sensor.
• If less than 5 ppm, replace the DPF.
• If the test passes
13. All OK.
Repair Instructions
* Catalytic Converter Replacement (L20,LMF) Service and RepairCatalytic Converter Replacement (V6) Service and RepairCatalytic Converter Replacement (LGH) Service and RepairCatalytic Converter Replacement (LC8,L96) Service and Repair
* Emission Reduction Fluid Exhaust Front Pipe Injector Supply Pipe Replacement Service and Repair
* Emission Reduction Fluid Injector Replacement Service and Repair
* Emission Reduction Fluid Tank Replacement Emission Reduction Fluid Tank Replacement
* Exhaust Particulate Filter Replacement (LGH-35 Series) Exhaust Particulate Filter Replacement (35 Series)Exhaust Particulate Filter Replacement (LGH) Exhaust Particulate Filter Replacement
* Nitrogen Oxide Sensor Replacement - Position 1 Nitrogen Oxide Sensor Replacement - Position 1
* Nitrogen Oxide Sensor Replacement - Position 2 Nitrogen Oxide Sensor Replacement - Position 2
Perform the scan tool reset procedures after replacing the reductant or any other components not including the DPF:
1. Clear the DTCs.
2. NOx Catalyst Reductant Loading Reset.
3. Emission Reduction Fluid Injector Quantity Test Emission Reduction Fluid Injector Quantity Test.
Note: The diesel exhaust fluid must be greater than -7°C (+19°F) and not in frozen tank status before proceeding with this procedure.
4. Verify the Reductant Fluid Quality Test (With or without DTCs) Component Tests and General Diagnostics passes when commanded ON with a scan tool. This test is necessary to verify system efficiency.
• If the test does not pass
A condition with the system still exists.
• If the test passes
5. All OK.
Perform the scan tool reset procedures after replacing the DPF:
1. Clear the DTCs.
2. NOx Catalyst Reductant Loading Reset
3. NOx Catalyst Reset
4. DPF/Catalyst 2 Reset
5. Perform the Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration to break in the DPF.
6. Verify the Reductant Fluid Quality Test (With or without DTCs) Component Tests and General Diagnostics passes when commanded ON with a scan tool. This test is necessary to verify system efficiency.
• If the test does not pass
A condition with the system still exists.
• If the test passes
7. All OK.
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.
Note: The diesel exhaust fluid must be greater than -7°C (+19°F) and not in frozen tank status before proceeding with this procedure.
5. Ignition ON.
6. Verify there are no leaks in the system when commanding the Reductant System Leak Test ON with a scan tool.
• If a leak is found
Repair as necessary
• If no leak is found
7. All OK.