Exhaust and emissionsModel years 2002–2018Manufacturer
P0420 / P0430 on a new or just-replaced catalytic converter (break-in not completed)
GMC Yukon Models 2002 - 2018, V8 (also Escalade, Avalanche, Express, Silverado, Suburban, Tahoe, Savana, Sierra, Hummer H models)
FaultCrate・P0420 / P0430 on a new or just-replaced catalytic converter (break-in not completed)
An SES light may occur on low-mileage vehicles or vehicles that recently had the catalytic converter replaced.
DTCs P0420 and/or P0430 may be stored.
The catalytic converter may not have completed a thorough break-in cycle after replacement, possibly resulting in a false DTC P0420 and/or P0430.
On a new vehicle, catalytic converter efficiency DTCs P0420 and P0430 are disabled for the first hour of engine run time to allow break-in of the catalytic converter.
If the engine run time is less than one hour, the battery may have been disconnected, or another vehicle power loss event may have occurred, during vehicle manufacturing.
If the DTCs set shortly after the catalytic converter is replaced, it may be because the engine run time restrictions are no longer in place since the vehicle is no longer new.
How to tell
What to do
- If the diagnostics still do not pass, perform SI diagnostics and repair as necessary.
- On a new/low mileage vehicle with these DTCs, use the Tech 2 to verify engine run time on the Engine Hour Meter in the IPC Data Display/Data 1 List.
- Finally, restart the engine and operate the vehicle at the conditions for running the DTC P0420/430 tests, and make sure the vehicle passes them.
- If this occurs, clear the DTCs and perform the drive cycle.
- Drive vehicle at sustained highway speed for 25 to 30 minutes.
- Drive cycle step: after the engine has been off for 1 minute, restart and resume highway speed for an additional 10 to 15 minutes.
What is needed
- Parts and materials
- Not stated
- Labor time
- Not stated
- Special tools
- Not stated
- Scan tool
- Not stated
Only what the technical documents state. "Not stated" does not mean not needed.
Applies to
- The bulletin lists GMC Yukon Models 2002 - 2018 with V8 engines.
See the evidence (3 documents, 13 passages)
| Document | Publisher | Date |
|---|---|---|
| [1]PIP3119P: Catalytic Converter Break-In Information To Prevent DTCs P0420 And/Or P0430 ↗ | ManufacturerGeneral Motors (published by NHTSA) | 2019-03-06 |
| [2]PIP3119P Catalytic Converter Break-In Information To Prevent DTCs P0420 And/Or P0430 ↗ | ManufacturerGeneral Motors | — |
| [3]PIP3119N Catalytic Converter Break-In Information To Prevent DTCs P0420 And/Or P0430 ↗ | ManufacturerGeneral Motors | — |
Applies toThe bulletin lists GMC Yukon Models 2002 - 2018 with V8 engines.
GMC Yukon Models 2002 - 2018 All All V8 ALL— [1] Models
First signsAn SES light may occur on low-mileage vehicles or vehicles that recently had the catalytic converter replaced.
A SES light may be experienced on low mileage vehicles, or vehicles that have recently had the catalytic converter replaced.— [1] Condition
First signsDTCs P0420 and/or P0430 may be stored.
Upon inspection, DTCs P0420 and/or P0430 may be stored.— [1] Condition
Why it happensThe catalytic converter may not have completed a thorough break-in cycle after replacement, possibly resulting in a false DTC P0420 and/or P0430.
the catalytic converter may not have completed a thorough break-in cycle after replacement, possibly resulting in a false DTC P0420 and/or P0430.— [1]
RepairIf this occurs, clear the DTCs and perform the drive cycle.
If this occurs, clear the DTCs and perform the drive cycle below.— [1]
RepairDrive vehicle at sustained highway speed for 25 to 30 minutes.
Drive vehicle at sustained highway speed for 25 to 30 minutes— [1] drive cycle step 1
How to confirmIf the diagnostics still do not pass, perform SI diagnostics and repair as necessary.
If the diagnostics do not pass, perform SI diagnostics and repair as necessary.— [1]
Why it happensOn a new vehicle, catalytic converter efficiency DTCs P0420 and P0430 are disabled for the first hour of engine run time to allow break-in of the catalytic converter.
On a new vehicle, catalytic converter efficiency DTCs P0420 and P0430 are disabled for the first hour of engine run time to allow break-in of the catalytic converter.— [2]
Why it happensIf the engine run time is less than one hour, the battery may have been disconnected, or another vehicle power loss event may have occurred, during vehicle manufacturing.
If the engine run time is less than one hour, the battery may have been disconnected, or another vehicle power loss event may have occurred, during vehicle manufacturing.— [2]
Why it happensIf the DTCs set shortly after the catalytic converter is replaced, it may be because the engine run time restrictions are no longer in place since the vehicle is no longer new.
If the DTCs set shortly after the catalytic converter is replaced, it may be a result of the engine run time restrictions no longer being in place since the vehicle is no longer new.— [2]
How to confirmOn a new/low mileage vehicle with these DTCs, use the Tech 2 to verify engine run time on the Engine Hour Meter in the IPC Data Display/Data 1 List.
If these DTCs are found on a new/low mileage vehicle, use the Tech 2 to verify engine run time on the Engine Hour Meter in the IPC Data Display/Data 1 List.— [2]
How to confirmFinally, restart the engine and operate the vehicle at the conditions for running the DTC P0420/430 tests, and make sure the vehicle passes them.
Restart the engine and operate vehicle at the conditions for running the DTC P0420/430 tests and assure that the vehicle passes these diagnostic tests.— [2]
RepairDrive cycle step: after the engine has been off for 1 minute, restart and resume highway speed for an additional 10 to 15 minutes.
Shut off the engine for 1 minute 4. Restart the engine and resume highway speed for an additional 10 to 15 minutes— [3]
Put together by FaultCrate from public records and technical documents. The cause and the repair are for the workshop to decide with the vehicle in front of it. Counts are records, not failure rates.
List the records (4 that can be opened)
Records whose recall number, document number or text matches. Each line says why it matched.
- Service Engine Soon Light at Low Mileage Diagnostic InformationManufacturer communication 2017-08-15・text contains "P0420"
- Service Engine Soon Lamp at Low Mileage - Catalytic Converter DiagnosticsManufacturer communication 2017-08-15・text contains "P0420"
- Service Engine Soon Lamp at Low MileageManufacturer communication 2017-08-15・text contains "P0420"
- Service Engine Soon Lamp at Low Mileage – Catalytic Converter DiagnosticManufacturer communication 2017-08-15・text contains "P0420"