P249E
P249E-CLOSED LOOP SCR REDUCTANT INJECTION CONTROL AT LIMIT - FLOW TOO HIGH
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation
The Powertrain Control Module (PCM) uses the NOx Sensor 1/1 feedback along with engine operating and environmental conditions to calculate the diesel exhaust fluid dosing rate. The DEF Dosing Control Unit will turn on the MIL Lamp via the PCM immediately after the monitor runs and fails. The DEF Dosing Control Unit will turn off the MIL Lamp via the PCM immediately after the monitor runs and passes.
- When Monitored:
This monitor runs when the engine is running and diesel exhaust fluid dosing is being commanded.
- Set Condition:
The DEF Dosing Control Unit detects that the NOx Sensor levels are higher than expected.
Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.
1. OTHER RELATED DTCS
1. Turn the ignition on.
2. With the scan tool, read DTCs.
Were there any DTCs present for the EGR System, DEF Injector, NOx Sensors, DEF Pump Assembly or DEF Dosing Control Unit?
Yes
- If this DTC is present along with any DEF Injector, NOx Sensors, DEF Pump Assembly or DEF Dosing Control Unit, repair those DTCs before proceeding.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Go To 2
2. CHECK THE EGR SYSTEM FOR LEAKS
1. Turn the ignition off.
2. Visually inspect the entire EGR system for soot streaking indicating a leak.
Were there any leaks found in the EGR system?
Yes
- Repair the EGR system.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Go To 3
3. CHECK FOR CYLINDER MISFIRE
1. Start the engine.
2. With the scan tool, navigate to Systems Tests, and perform the Injector Kill system test.
Were any cylinders found to be faulty or low?
Yes
- Perform the CHECKING ENGINE MISFIRE / RUNS ROUGH / PERFORMANCE TEST diagnostic procedure. . Checking Engine Misfire / Runs Rough / Performance Test
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Go To 4
4. CHECK THE ENGINE PERFORMANCE
1. Perform the CHECKING ENGINE MISFIRE / RUNS ROUGH / PERFORMANCE TEST diagnostic procedure.. Checking Engine Misfire / Runs Rough / Performance Test
Were any problems found?
Yes
- Perform the appropriate repair.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.
No
- Replace the DEF Injector. Diesel Exhaust Fluid Injector - Removal.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.