GLOBAL SAFETY FIELD INVESTIGATIONS
DCS5649
URGENT - DISTRIBUTE IMMEDIATELY
Date:

January 20, 2021

Subject: N202321230 - Service Update
Improper Assembly of Heater Hoses to Auxiliary Pump
Models: 2021 Chevrolet Suburban
2021 Chevrolet Tahoe
2021 GMC Yukon
2021 GMC Yukon XL
To:

All General Motors Dealers

General Motors is releasing Service Update N202321230 today. The total
number of U.S. vehicles involved is 141. Please see the attached bulletin for
details.
Global Warranty Management (GWM)
The Required Field Action section on the Investigate Vehicle History (IVH) screen will
be updated January 21, 2021 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
N202321230 Improper Assembly of Heater Hoses to Auxiliary Pump
Release Date:
Attention:

January 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
Chevrolet
GMC
GMC

Model
Suburban
Tahoe
Yukon
Yukon XL

Model Year
From
To
2021

RPO

Description

2021

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 2021 model year Chevrolet Suburban and Tahoe, and GMC Yukon and Yukon XL vehicles
were built with the horizontal hose on the auxiliary heater coolant pump misassembled. The clamp
may not be properly aligned and positioned on the hose, or the hose is rolled over on the pump port.
The improper assembly can quickly develop into a significant leak early in the truck’s life. As the
coolant level drops, a Low Coolant Warning or potential for engine overheat with DIC message is
possible.
Dealers are to inspect for both the vertical and horizontal hose at the auxiliary coolant pump, and repair
as needed.

Parts
Quantity
4
1
1

Part Name

Part No.
12346290
84545534
90572594

Engine Coolant
Auxiliary Heater Water Pump Hose
Hose Clamp

Parts should only be ordered when inspection determines that it is necessary to replace.
It is estimated that only 175 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
9105517
9105518
9105519

Description
Inspect Only – No Further Action Required
Realign clamps (Includes Inspection)
Fix rolled hose, leak check
Add: Replace Heater Water Pump Hose

Labor
Time
0.2
0.3
1.1
0.8

Trans.
Type
ZFAT
ZFAT
ZFAT

Net
Item
N/A
N/A
N/A

Service Procedure
1.

Lift the vehicle. Refer to Lifting and Jacking the Vehicle in SI.

Copyright 2021 General Motors. All Rights Reserved.

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Service Update
N202321230 Improper Assembly of Heater Hoses to Auxiliary Pump

2.

5694874
Locate the heater auxiliary water pump, visible between the frame rail and the skid plate on the passenger’s side of
the engine bay.

5694875
3.

4.

Inspect the hose clamps on the heater water pump hose and be sure they are properly aligned on the hose barbs
and hose, as shown here. Also make sure the hose ends are not rolled over.
•

If the hose clamps are properly aligned and the hose ends are not rolled over, no further action is required.
Proceed to step 6.

•

If the hose clamps are improperly aligned, reposition them properly so they fully clamp the hose over the
water pump barb. Then proceed to step 5.

•

If the hose end is rolled over, drain the coolant (refer to Coolant System Draining and Filling in SI) remove
the hose end from the water pump and reinstall it properly.

Pressurize the cooling system with the EN-24460-A Cooling System Pressure Tester per Coolant System Leak
Testing in SI and observe the heater auxiliary water pump hose connections for leaks.
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Service Update
N202321230 Improper Assembly of Heater Hoses to Auxiliary Pump
•

If the heater auxiliary water pump hose connections are leaking, replace the Heater Water Auxiliary Pump
Hose and clamp. Refer to Heater Water Auxiliary Pump Hose Replacement in SI.

•

If the heater auxiliary water pump hose connections are NOT leaking, no further action is required.

5.

Refill any coolant that was lost during step 3. Refer to Coolant System Draining and Filling in SI.

6.

Lower the vehicle. Refer to Lifting and Jacking the Vehicle in SI.

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
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