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P249E




DTC P249D or P249E

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 P249D

-
Closed Loop Reductant Injection Control At Limit - Flow Too Low

DTC P249E

-
Closed Loop Reductant Injection Control At Limit - Flow Too High

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

* DTCs P0101, P0401, P0402, P0420, P11DB, P11DC, P140B, P140C, P207F, P2200, P2202, P2203, P2205, P2209, P229E, P229F, P22A3, P22A7, or U029D, or U029E 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 DTCs run continuously once the above conditions are met.

Conditions for Setting the DTC

The ECM detects an out of range high or low dosing control factor.

Action Taken When the DTC Sets

DTCs P249D and P249E are Type B DTCs.

Conditions for Clearing the DTC

DTCs P249D and P249E are Type B DTCs.

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

Circuit/System Verification

1. Ignition ON, observe the DTC information with a scan tool. Verify that DTCs P0101, P0400, P0401, P0402, P0420, P11CB, P11CC, P11DB, P11DC, P140B, P140C, P2200, P2201, P2202, P2203, P2205, P2209, P229E, P229F, P22A0, P22A1, P22A3, P22A7, P2413, PC29D, or PC29E are not set.

• If a DTC is set, refer to Diagnostic Trouble Code (DTC) List - Vehicle Diagnostic Trouble Code (DTC) List - Vehicle for further diagnosis.

2. Test the diesel exhaust fluid for contamination. Refer to Contaminants-in-Diesel Exhaust Fluid Diagnosis Contaminants-in-Diesel Exhaust Fluid Diagnosis.

• If the diesel exhaust fluid is contaminated, replace the diesel exhaust fluid.

3. Remove the Q61 emission reduction fluid injector from the exhaust pipe leaving the reductant line and electrical connector connected. Place the Q61 emission reduction fluid injector into a suitable container.

4. Ignition ON, command the Reductant System Leak Test ON with a scan tool. Allow the pressure to build at least 400 kPa (58 psi). Verify there are no leaks in the reductant lines or Q61 emission reduction fluid injector.

• If a condition is found, replace the Q61 emission reduction fluid injector.

5. 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.

6. Verify the following conditions do not exist:

* Leaking Q57 Indirect fuel injector-Refer to Indirect Fuel Injector Diagnosis Component Tests and General Diagnostics

* Leaking fuel injectors

* Engine oil or coolant consumption

* Engine mechanical condition

• If a condition is found, repair as necessary

7. Verify the following conditions do not exist with the SCR:

* Physical damage or alterations

* Internal rattles caused by a damaged catalyst substrate

* Leaks in the exhaust system-Refer to Exhaust Leakage Exhaust Leakage for further diagnosis.

• If a condition is found, repair as necessary.

8. Loose B195 NOx sensors or B131 exhaust temperature sensors-refer to DTC P11CB-P11CD, P11DB, P11DC, P2201, or P229F P11CB for further diagnosis.

9. Engine running and at operating temperature, with a scan tool, verify NOx 2 NOx Concentration is less than NOx 1 NOx Concentration.

• If NOx 2 NOx Concentration is greater than NOx 1 NOx Concentration, replace the B195 nitrogen oxide sensor - position 2.

10. Disconnect the Q61 emission reduction fluid injector electrical connector.

11. Idle engine at 1500 RPM for 10 minutes while monitoring NOx 1 and NOx 2 NOx Concentration.

• If NOx 2 NOx Concentration value does not approach NOx 1 Concentration value, replace the B195 nitrogen oxide sensor - position 2.

12. Install any components or connectors that have been removed or replaced during diagnosis.

13. If all components and fluid test normal, replace the SCR.

Repair Instructions

* 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 (LGH-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 following scan tool reset procedures after replacing the DEF or any other components not including the SCR/DPF:

1. NOx Catalyst Reductant Loading Reset

2. Perform the Diesel Particulate Filter (DPF) Service Regeneration Diesel Particulate Filter (DPF) Service Regeneration

3. Perform the Reductant Fluid Quality Test Component Tests and General Diagnostics. This test is necessary to reset the Reductant System history. Disregard the test results.

* Perform the following scan tool reset procedures after replacing the SCR/DPF:

1. NOx Catalyst Reductant Loading Reset

2. NOx Catalyst Reset

3. DPF/Catalyst 2 Reset

4. Perform the Reductant Fluid Quality Test Component Tests and General Diagnostics. This test is necessary to reset the Reductant System history. Disregard the test results.

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 (DEF) and ambient air temperatures must be greater than -7°C (19°F) before proceeding with this procedure.

5. 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) and there should be no leaks in the system.

6. Engine idling, verify with a scan tool that NOx 2 NOx Concentration is less than NOx 1 NOx Concentration.

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.

7. Engine idling at operating temperature. Accelerate at part throttle to 90 km/h (55 mph) with this speed maintained until the average SCR temperature is between 240-290°C (464-554°F).

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