P214B

P214B-SCR NOx CATALYST INLET TEMPERATURE TOO HIGH DURING PARTICULATE FILTER REGENERATION

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

Theory of Operation

The Selective Catalytic Reduction (SCR) Catalyst is used in combination with the Diesel Exhaust Fluid system to reduce the amount of NOx gases produced during engine combustion. Excessive fuel or oil entering the exhaust system due to a failed engine component or Fuel Injector can cause the temperature to rise and will result in damage to the SCR Catalyst. The DEF Dosing Control Unit will turn on the MIL Lamp via the Powertrain Control Module (PCM) immediately after the monitor runs and fails, and diesel exhaust fluid injection is disabled.

- When Monitored:
Continuously with the engine running and active regeneration of the DOC/DPF Catalyst is occurring.

- Set Condition:
The Powertrain Control Module detects that Exhaust Gas Temperature (EGT) Sensor 1/3 is above 800°C (1472°F) for more than 20 seconds.





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

1. CHECK THE OPERATION OF EXHAUST TEMPERATURE SENSORS

NOTE: This DTC will change to stored immediately after the exhaust temperature drops below the limit and will likely be stored when it enters the shop. For this reason, the diagnostic procedure should be performed for both active and inactive DTCs.

NOTE: Repair any fuel, emissions, or DEF system component DTCs before continuing with this diagnostic procedure.

1. Start and idle the engine for 10 minutes.
2. With the scan tool, read and compare the Exhaust Gas Temperature (EGT) Sensors.

Do any of the EGT Sensors vary more than 43°F of the others?

Yes

- Go To 2

No

- Go To 3

2. CHECK THE EXHAUST TEMPERATURE SENSOR FOR A SHORT TO ANOTHER CIRCUIT

NOTE: Perform this test on the EGT Sensor that was reading more than 43°F above or below the others.

1. Turn the ignition off.
2. Disconnect the Powertrain Control Module (PCM) C2 harness connector.
3. Measure the resistance between the EGT Sensor Signal circuit and all other circuits in the PCM C2 harness connector.

Was the resistance above 10k Ohms between the EGT Sensor Signal circuit and all other circuits in the PCM C2 harness connector?

Yes

- Replace the Exhaust Gas Temperature Sensor. Removal.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- Repair the short between the Exhaust Gas Temperature Sensor circuit and the circuit that measured below 10k Ohms.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

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 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 5

5. CHECK THE DOC/DPF CATALYST FOR PLUGGING
1. Remove the DOC/DPF Catalyst and check the inlet side for signs of soot accumulation or face plugging.

Does the DOC/DPF Catalyst show any evidence of face plugging or soot accumulation?

Yes

- If DTC P1451 is present, perform a scan tool initiated regeneration of the after treatment system.
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.

No

- If DTC P1451 is not present, replace the DOC/DPF assembly. Removal and Replacement
- Perform the POWERTRAIN VERIFICATION TEST - 6.7L. Powertrain Verification Test.