GLOBAL SAFETY FIELD INVESTIGATIONS
DCS5736
URGENT - DISTRIBUTE IMMEDIATELY
Date:

March 29, 2021

Subject: N202315731 - Service Update
Wheel Casting with Exposed Porosity on Extra Set of Wheels
Models: 2020 Chevrolet Corvette
To:

All General Motors Dealers

General Motors is releasing Service Update N202315731 today. The total
number of U.S. vehicles involved is approximately 1,767. Please see the
attached bulletin for details.
Certain VINs under N202315730 have two sets of wheels. This Service
Update addresses the extra set of wheels. For wheels currently on the
vehicle, those are inspected under N202315730.
Global Warranty Management (GWM)
The Required Field Action section on the Investigate Vehicle History (IVH) screen will
be updated March 30, 2020 or sooner. A list of involved vehicles in dealer new
inventory is attached to this message. Please hold all warranty transactions until IVH
has been updated.
END OF MESSAGE
GLOBAL SAFETY FIELD INVESTIGATIONS

Service Update
N202315731 Wheel Casting with Exposed Porosity on Extra Set of
Wheels
Release Date:
Attention:

March 2021

Revision:

00

This service update includes vehicles in dealer inventory and customer vehicles that return to the
dealership for any reason. This bulletin will expire at the end of the involved vehicle’s New Vehicle Limited
Warranty period.

Make
Chevrolet

Model
Corvette

Model Year
From
To
2020
2020

RPO

Description

Involved vehicles are marked “open” on the Investigate Vehicle History screen in GM Global Warranty Management
system. This site should always be checked to confirm vehicle involvement prior to beginning any required inspections
and/or repairs.
Condition

Correction

Certain 2020 model year Chevrolet Corvette vehicles may have a condition where exposed porosity in
wheel castings are larger than allowed and do not meet internal GM requirements. Vehicles in this field
action are to have two sets of wheels inspected. The wheels on the vehicle are inspected under
N202315730 and the extra wheels are inspected under this field action.
Dealers are to inspect the wheels and replace if necessary.

Parts
Quantity
As Required
As Required
As Required
As Required
As Required
As Required
As Required
As Required
As Required
As Required
As Required
As Required

Part Name

Part No.
84785086
84785088
84785085
84785087
84600213
84723820
84600212
84723819
23417380*
84735859*
84787695
84787697

Wheel
Wheel
Wheel
Wheel
Wheel
Wheel
Wheel
Wheel
Wheel
Wheel
Wheel
Wheel

*This part is an Accessory part and is sold in a package qty of 8. Dealers should not be order through GMCCA.
Dealers should order this part from their local ADI. This part will be reviewed and canceled daily.
It is estimated that only 10% of involved vehicles will require parts replaced. Due to the small number of vehicles
anticipated that will need this fix and the limited initial parts availability, dealers are encouraged not to order
these parts for use as shelf stock.
Reminder: Parts may be removed from Retail Inventory Management (RIM). Dealers should review the affected parts
to confirm RIM managed status. Parts may have quantity limiters in effect.
Warranty Information
Labor
Operation
9105363
9105364*

Description
Inspect 4 Road Wheels - No Further Action Required
Replace First Road Wheel, Includes Inspection
Add: Each Additional Wheel

Labor
Time
0.2
0.5
0.3

Trans.
Type

Net
Item

ZFAT

N/A

*Note: This labor operation requires submittal via the Certified Service Mobile Toolbox (CSMT) App, in the Pre-Repair
Authorization (PRA) section. The component name in the PRA is “Field Action” and the defect is “Wheel-N202315731”.
Please see bulletin 18-NA-306 for further details.
Service Procedure
This procedure applies to the extra set of wheels. Do not perform this procedure on wheels that are mounted
on the vehicle.
Caution: To avoid surface damage on wheels and wheel trim, do not use strong soaps, chemicals, abrasive polishes,
cleaners, or brushes. Use only GM approved cleaners or the equivalent.
Copyright 2021 General Motors. All Rights Reserved.

Page 1 of 6

Service Update
N202315731 Wheel Casting with Exposed Porosity on Extra Set of
Wheels
1.

If required, clean the wheels using an appropriate cleaning solution. Use care to not damage the wheels with nonapproved cleaners.

2.

Thoroughly inspect the front side, back side, and rim of the wheels for porosity in the surface of the metal. Porosity
examples are shown below in circles.

The following photos show examples of the porosity condition covered by this bulletin.
Rim:

5754336

Front Side of Spoke:

5754340

Page 2 of 6

Service Update
N202315731 Wheel Casting with Exposed Porosity on Extra Set of
Wheels
Back Side of Spoke near Rim:

5754354

Back Side of Spoke near Rim:

5754356

Page 3 of 6

Service Update
N202315731 Wheel Casting with Exposed Porosity on Extra Set of
Wheels
Back Side of Spoke:

5754359

Back Side of Spoke:

5754360

Page 4 of 6

Service Update
N202315731 Wheel Casting with Exposed Porosity on Extra Set of
Wheels
Back Side of Spoke near Hub:

5754361

Note: Each wheel must be individually and thoroughly inspected to avoid invalid submissions. Do NOT automatically
replace all four wheels on the vehicle.
3.

If any of the above conditions are found, initiate the Pre-Repair Authorization (PRA) process for a wheel
replacement authorization:
US and Canadian Dealers:
Need to submit a Pre-Authorization (PRA) in the Certified Service Mobile Toolbox (CSMT) app using the process in
18-NA-306. Dealers will still claim under the labor code 9105364 in the Warranty Information table. In the PRA,
be sure to select the Component as “Wheel” and the Defect is “Field Action”.
Quebec Dealers:
Take photos that clearly illustrates the porosity in the wheel. If multiple wheels are being replaced, identify the
removal location from the vehicle on each wheel before taking the photo.
Attach photos to the GWM transaction and H-route for WSC agent approval.
Middle East Regions:
If any of the above conditions are found, initiate the Pre-Repair Authorization (PRA) process for a replacement
wheel replacement authorization. Append pictures of the affected wheels to the PRA for your ATWM’s review and
approval.

Note: This bulletin is intended to address wheel casting porosity only. For any other warrantable cosmetic concerns
discovered during the wheel inspection, refer to 18-NA-306 for replacement wheel authorization.
4.

If required, install the customer’s tire onto the new service wheel (or wheels). Refer to Tire Dismounting and
Mounting in SI.

5.

Once the new wheel replacement has been approved and the new wheel (or wheels) are mounted, the defective
wheel (or wheels) need to be properly disposed of.

Page 5 of 6

Service Update
N202315731 Wheel Casting with Exposed Porosity on Extra Set of
Wheels

5754219

•

Drill a 13mm (1/2 in.) hole completely through the rim barrel of the wheel.

•

Recycle the unusable wheel with a reputable metal recycler.

Dealer Responsibility
Whenever a vehicle subject to this service update enters your vehicle inventory or is in your facility for service in the
future, and the vehicle is still covered under the New Vehicle Limited Warranty, you must take the steps necessary to be
sure the service update correction has been made before selling or releasing the vehicle.
All new, used, GM Certified Used, courtesy transportation vehicles, dealer shuttle vehicles, etc. in dealers' possession
and subject to this bulletin must be held and inspected/repaired per the service procedure of this bulletin before customers
take possession of these vehicles. Involved vehicles must be held and not delivered to customers, dealer-traded,
released to auction, used for demonstration, or any other purpose.
All GM Certified Used vehicles currently in the dealers’ inventory within the Certified Pre-Owned Inventory System
(CPOIS) will be de-certified and must be held and remedied per the service procedure in this bulletin. Upon submitting
an accepted/paid warranty transaction in the Global Warranty Management (GWM) system, the vehicle can be re-certified
for sale within the CPOIS system, or once again be used in the CTP program.
Dealer Reports
The Inventory tab of the Open Vehicle Report will contain Service Update Bulletin VINs that apply to this field action.
This information is intended to assist dealers with the PROMPT COMPLETION of these vehicles. The Customer InService tab will not contain Service Update Bulletin VIN data because the intent of a Service Update Bulletin is to not
inconvenience a customer with a special trip for service. Service Update Bulletins are to be completed when the
customer is in for a regularly scheduled visit.

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 tools, equipment, 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 dealer for information on whether your
vehicle may benefit from the information.

We Support
Voluntary Technician
Certification

Page 6 of 6