P207F

P207F-REDUCTANT QUALITY PERFORMANCE
For a complete wiring diagram, refer to the Wiring Information.
Theory of Operation

The Diesel Exhaust Fluid system is used to reduce the amount of NOx being discharged through the exhaust system. The DEF Dosing Control Module receives feedback from the two NOx Sensors in the system. The first NOx Sensor is located before the SCR Catalyst, and the second NOx Sensor is located at the outlet of the SCR Catalyst. The DEF Dosing Control Module compares the two values to determine the conversion efficiency of the SCR Catalyst and the Diesel Exhaust Fluid system. The DEF Dosing Control Unit will illuminate the MIL light via the Powertrain Control Module (PCM) immediately after the diagnostics runs and fails.

- When Monitored:
This monitor runs after the DEF Tank has been refilled. NOx sensor data is gathered over varying engine speeds and loads. When enough data has been gathered, the diagnostic will run, make a pass/fail decision, and begin to gather data again.

- Set Condition:
The DEF Dosing Control Module detects that the NOx conversion rate across the SCR Catalyst is lower than expected and the tank has been recently refilled.





Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. Pre-Diagnostic Troubleshooting Procedure.

1. CHECK THE DIESEL EXHAUST FLUID

NOTE: Repair any DEF system component DTCs before continuing with this diagnostic procedure.

1. Collect a sample of diesel exhaust fluid from the system.
2. Visually inspect the fluid for signs of contamination or debris.
3. Test the quality of the fluid using litmus paper (supplied by parts) or by using an SPX DEF/UREA Refractometer 94-F-00K-108-456 or equivalent.

NOTE: The diesel exhaust fluid should register approximately 9 ph with the litmus paper and 32.5 percent using a refractometer.

Is the diesel exhaust fluid quality within specification and free of debris and contamination?

Yes

- Go To 2

No

- Drain the diesel exhaust fluid from the tank and fill the system. If the fluid is contaminated, follow the cleaning procedure. Procedures.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

2. CHECK THE EXHAUST SYSTEM FOR LEAKS
1. Visually inspect the entire exhaust system for signs of a leak.

Were any exhaust leaks found?

Yes

- Perform the appropriate repair.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 3

3. CHECK THE DEF INJECTOR DECOMP TUBE FOR DEPOSITS

NOTE: The diesel exhaust fluid will form hard deposits when exposed to air.

1. Remove the DEF Injector from the Decomp Tube. Diesel Exhaust Fluid Injector - Removal.
2. Visually inspect the Decomp Tube for diesel exhaust fluid deposits.

Were any deposits found?

Yes

- Clean the deposits from the Decomp Tube.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. CHECK THE DEF INJECTOR
1. Reconnect the DEF Injector harness connector.
2. Place the DEF Injector in a container to capture the fluid sprayed.
3. Turn the ignition on.
4. With the scan tool, navigate to Systems Tests and actuate the Diesel Exhaust Fluid Doser Pump Override Test.

NOTE: This Test will run for six minutes before timing out. The amount of flow may fluctuate through out the test, therefore the test must be allowed to run completely in order for the results to be accurate. The fluid should spray out as a mist. There should be no dripping from the holes in the DEF Injector at any time during the duration of the test procedure.

5. Measure the amount of fluid sprayed after the test times out.

Does the fluid sprayed measure between 85 ml and 115 ml?

Yes

- Replace the SCR Catalyst.
- 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.