P229F

P229F-AFTERTREATMENT NOx SENSOR CIRCUIT PERFORMANCE - BANK 1 SENSOR 2





For a complete wiring diagram, refer to the Wiring Information.

Theory of Operation

The after treatment system is equipped with two Nox Sensors and modules. The upstream NOx Sensor 1/1 is located before the SCR Catalyst and is permanently connected to a corresponding Nox Sensor Module mounted on the right frame rail. The downstream NOx Sensor 1/2 is located at the outlet of the SCR Catalyst and is permanently connected to a corresponding Nox Sensor Module also mounted on the right frame rail. The NOx Sensors and NOx Sensor Modules are calibrated to each other and must be replaced as an assembly. The two NOx Sensor and Module assemblies are not interchangeable. The NOx Sensor Modules are smart devices and communicate with the Powertrain Control Module (PCM) over the J1939 Data Link. The NOx Sensor Modules perform their own internal diagnostics and report malfunctions back to the PCM. The NOx Sensors are used to monitor the efficiency of the SCR Catalyst and dosing system. The PCM will illuminate the MIL lamp immediately after the monitor runs and fails. The PCM will turn off the MIL Lamp after the monitor runs and passes for three consecutive trips.

- When Monitored:
This diagnostic monitor consists of two separate checks. The first check occurs when the engine exhaust temperature at NOx Sensor 1/2 is above 150°C (302°F), and the engine is in a decel condition and zero fueling. The second check occurs when the engine exhaust temperature at NOx Sensor 1/2 is above 150°C (302°F), and the calculated NOx value is changing.

- Set Condition:
The Powertrain Control Module detects that the NOx Sensor 1/2 reading is not reading zero during decel condition and zero fueling for two consecutive trips or the PCM has detected that the NOx Sensor 1/2 reading is not changing with engine conditions for two consecutive trips.





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

1. ACTIVE DTC

NOTE: If DTCs P220B, P229E, or P22A7 are present, perform the diagnostic for those DTCs before continuing with this test procedure.

1. Start the engine, monitor Exhaust Gas Temperature Sensor 4 until it reaches 150°C (302°F).
2. Drive the vehicle at 50 MPH, ensure that it is not in DPF Regeneration mode.
3. Perform a zero fueling event (decel condition for 10 seconds, with foot off of accelerator pedal).
4. Repeat this condition three to five times.
5. With the scan tool check active DTCs.

Is the DTC active?

Yes

- Go To 2

No

- Perform the INTERMITTENT CONDITION - 6.7L diagnostic procedure. Intermittent Condition Test

2. 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 3

3. CHECK FOR EXCESSIVE ENGINE OIL BEING INTRODUCED INTO THE AFTERTREATMENT SYSTEM
1. Turn the ignition off.
2. Remove the turbocharger outlet and inspect for signs of oil, fuel or moisture being introduced into the after treatment system from the engine.

Was engine oil, fuel or moisture found in the turbocharger exhaust outlet?

Yes

- Locate the cause of possible diesel fuel or engine oil being carried from the engine into the exhaust system. Inspect the SCR Catalyst for possible damage.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 4

4. CHECK THE DECOMPOSITION TUBE FOR DIESEL EXHAUST FLUID DEPOSITS
1. Remove the DEF Injector. Diesel Exhaust Fluid Injector - Removal.
2. Visually inspect the Decompostion Tube for signs of diesel exhaust fluid crystals or deposits.

Were any deposits found?

Yes

- Remove the crystallization build up.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Go To 5

5. 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 NOx Sensor 1/2.
- 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.