Just looking at my paper work and looks as if the engine threw this code... PO420

What is this code ? They replaced the exhaust. Thanks

 

P0420-CATALYST EFFICIENCY BANK 1
For a complete wiring diagram Refer to Section 8W.

Theory of Operation
The aftertreatment diesel oxidation catalyst is designed to react with hydrocarbons in the exhaust stream, this chemical reaction reduces hydrocarbon emission levels and also produces heat. Periodically, the ECM will utilize the heat generated by this reaction in the aftertreatment diesel oxidation catalyst to actively regenerate and clean the aftertreatment diesel particulate filter. This diagnostic checks that the aftertreatment diesel oxidation catalyst is present and functioning correctly. The ECM monitors the efficiency of the aftertreatment diesel oxidation catalyst through interpretation of data received from the aftertreatment diesel oxidation catalyst inlet and diesel particulate filter inlet temperature sensors, the monitor checks for a temperature rise across the aftertreatment diesel oxidation catalyst. The ECM will set the fault if it detects that the aftertreatment diesel oxidation catalyst is not present in the aftertreatment/exhaust system. The ECM will illuminate the MIL lamp immediately when the diagnostic runs and fails. The ECM will turn off the MIL lamp immediately after the diagnostic runs and passes.

When Monitored:
This diagnostic runs when the engine is running, and performing an active regeneration of the aftertreatment particulate filter.

Set Condition:
The ECM will set the fault if it detects that the aftertreatment diesel oxidation catalyst is not present in the aftertreatment/exhaust system.

Possible Causes
AFTERTREATMENT DIESEL OXIDATION CATALYST HAS BEEN REMOVED FROM THE VEHICLE
AFTERTREATMENT DIESEL OXIDATION CATALYST IS DAMAGED OR NOT FUNCTIONING PROPERLY
AFTERTREATMENT DIESEL OXIDATION CATALYST INLET AND/OR OUTLET TEMPERATURE SENSORS ARE DAMAGED/FAILED
IMPROPER FUELING
WIRING HARNESS


Always perform the Pre-Diagnostic Troubleshooting procedure before proceeding. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)




Diagnostic Test
1. OTHER DTC'S

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Ignition on, engine not running.
With the scan tool, read DTC's.

Are any other DTC's Active?

Yes
Repair other DTC's.
Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

No
Go To 2


2. EXHAUST LEAK

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Perform the no trouble code test *CHECKING THE EXHAUST SYSTEM FOR LEAKS.

Are leaks found?

Yes
Repair or replace as necessary.
Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

No
Go To 3


3. AFTERTREATMENT DIESEL OXIDATION CATALYST INLET AND/OR OUTLET TEMPERATURE SENSORS

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Remove and inspect the aftertreatment diesel oxidation catalyst and temperature sensors for damage and presence.

Are the components found to be damaged or missing during the inspection of the aftertreatment diesel oxidation catalyst and temperature sensors?

Yes
Replace or repair damaged component(s).
Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

No
Go To 4


4. EXHAUST GAS TEMPERATURE SENSOR #1 AND #2 ARE FUNCTIONAL.

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For Manual Transmission Vehicle.

1. Run the engine at Idle for at least 10 to 12 minutes with the vehicle in PARK.

2. Check that Exhaust temperature sensor #1 and Exhaust temperature sensor #2 are within 150° F - 200° F of each other.
For Automatic Transmission Vehicle.

1. Run the engine at Idle for at least 10 to 12 minutes with the PARKING BRAKE ON.

2. Check that Exhaust temperature sensor #1 and Exhaust temperature sensor #2 are within 150° F - 200° F of each other.

Is Exhaust temperature sensor #1 and Exhaust temperature sensor #2 are within 150° F - 200° F of each other?

Yes
Go To 5

No
Replace both exhaust temperature sensors.
Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)


5. AFTERTREATMENT DIESEL OXIDATION CATALYST IS DAMAGED OR NOT FUNCTIONING PROPERLY

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Remove the exhaust plumbing from the turbocharger outlet.
Inspect for signs of oil, coolant or fuel being introduced into the aftertreatment system from the engine or signs of moisture in the turbocharger exhaust outlet.

Is contamination found in the turbocharger exhaust outlet?

Yes
Identify and repair the source of the contamination within the engine and replace the aftertreatment diesel oxidation catalyst after the engine failure has been repaired
Perform POWERTRAIN VERIFICATION TEST - 6.7L. (Refer to 9 - ENGINE - STANDARD PROCEDURE)

No
Go To 6


6. AFTERTREATMENT DIESEL OXIDATION CATALYST

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Is DTC P0420 Active?

Yes
Replace aftertreatment diesel oxidation catalyst then clear the DTC.

No
Refer to the INTERMITTENT CONDITION - DIESEL Symptom. (Refer to 9 - ENGINE - DIAGNOSIS AND TESTING)

 

WOW !!! Awesome !