PIP3119L

Bulletin No.: PIP3119L
Date: Jun-2013
Subject:
Catalytic Converter Break-In Information To Prevent DTCs P0420 And/Or P0430
Models:
2004 - 2013 Cadillac Escalade, Escalade Hybrid
2004 - 2013 Chevrolet Avalanche, Express, Silverado, Silverado Hybrid, Suburban, Tahoe, Tahoe Hybrid
2004 - 2013 GMC Savana, Sierra, Sierra Hybrid, Yukon, Yukon Hybrid
2003 - 2009 Hummer H2
2008 - 2009 Hummer H3
With a V8 Engine (gas only)
This PI was superseded to reflect gas engines only. Please discard PIP3119J.
The following diagnosis might be helpful if the vehicle exhibits the symptom(s) described in this PI.
Condition/Concern
A SES light may be experienced on low mileage vehicles, or vehicles that have recently had the catalytic converter replaced.
Upon inspection, DTCs P0420 and/or P0430 may be stored.
Recommendation/Instructions
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.
The following scenarios may allow a DTC P0420 or P0430 to set after this hour of engine run time has expired.
1.
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. 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.
This may allow the catalyst efficiency diagnostics to run before one hour of engine run time has been achieved. If this occurs, the catalytic converter
may not have completed a thorough break-in cycle, causing a false DTC P0420 and/or P0430 to set.
If this occurs, clear the DTCs and perform the drive cycle below.
2.
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. As a result, the catalytic converter may not have completed a thorough break-in cycle after replacement, possibly resulting in a
false DTC P0420 and/or P0430. If this occurs, clear the DTCs and perform the drive cycle below.
In order to achieve proper catalytic converter temperature and allow the mat material to out-gas (break-in), perform the following drive cycle and
suggestions:
1.
Drive vehicle at sustained highway speed for 25 to 30 minutes
2.
Bring vehicle to a stop
3.
Shut off the engine for 1 minute
4.
Restart the engine and resume highway speed for an additional 10 to 15 minutes
5.
Bring vehicle to a stop
6.
Shut off engine for 1 minute
7.
Restart the engine and operate vehicle at the conditions for running the DTC P0420/430 tests and assure that the vehicle passes these diagnostic
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tests.
If the diagnostics for DTC P0420 and P0430 have passed, return the vehicle to customer for evaluation.
If the diagnostics do not pass, perform SI diagnostics and repair as necessary.
Warranty Information
For vehicles repaired under warranty, please use the appropriate warranty labor operation based on the actual cause and repair.
Please follow this diagnostic or repair process thoroughly and complete each step. If the condition exhibited is resolved without completing every step, the
remaining steps do not need to be performed.
GM bulletins are intended for use by professional technicians, NOT a "do-it-yourselfer". They are written to inform these technicians of conditions that may
occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools,
safety instructions, and know-how to do a job properly and safely. If a condition is described, DO NOT assume that the bulletin applies to your vehicle, or that
your vehicle will have that condition. See your GM dealer for information on whether your vehicle may benefit from the information.
WE SUPPORT VOLUNTARY TECHNICIAN CERTIFICATION
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