21-NA-132

Bulletin No.:
Service Bulletin
Date:
21-NA-132
January, 2024
INFORMATION
Subject:
Changes to the Automatic Stop/Start Feature for Certain 2021/2022 Escalade Models,
Cheyenne, Silverado 1500, Suburban, Tahoe, Sierra 1500, Yukon Models Equipped with
RPO NSS
Brand:
Model:
Cadillac
Escalade Models
Model Year:
VIN:
from
to
from
to
2021
2022
-
-
Engine:
Transmission:
L84 or L87
MQB, MQC,
MHS, or MHT
Cheyenne
Chevrolet
Silverado 1500
Suburban
Tahoe
GMC
Sierra 1500
Yukon Models
Involved Region or Country
Pickup: United States, Canada, Mexico, Australia and New Zealand
SUV: United States, Canada, Mexico, Middle East
Additional Options (RPOs)
• RPO NSS – Not Equipped with Automatic Stop/Start System
• Affected vehicles will continue to include RPO KL9 – Automatic Stop/Start System,
(for content which will remain)
• Affected vehicles will include RPO NSS (for affected system content)
Information
Important: Service agents must comply with all
International, Federal, State, Provincial, and/or
Local laws applicable to the activities it performs
under this bulletin, including but not limited to
handling, deploying, preparing, classifying,
packaging, marking, labeling, and shipping
dangerous goods. In the event of a conflict between
the procedures set forth in this bulletin and the
laws that apply to your dealership, you must follow
those applicable laws.
Beginning in June 2021, most 2021 Escalade models,
Cheyenne, Silverado 1500, Suburban, Tahoe, Sierra
1500, Yukon models equipped with L84 or L87 with
MQB or MQC 10-speed transmissions will be produced
without the Automatic Stop/Start feature.
Pickup and SUV models equipped with L84 or L87 with
MQB or MQC which are produced without Automatic
Stop/Start function will be identified with New RPO
NSS (Not Equipped with Automatic Stop/Start).
Copyright 2024 General Motors LLC. All Rights Reserved.
Considerations for Diagnosing Base
Engine or Electrical Wiring Concerns
Certain system components related to Automatic Stop/
Start (KL9) will be unchanged in vehicles equipped with
NSS: T19 - Multifunction Power Supply Converter,
Starter Motor, Battery, Wiring and Connectors. For
vehicles equipped with NSS, the Automatic Stop/Start
disable switch will not be present, the instrument
cluster will no longer show “Auto Stop,” and some
internal transmission components have been omitted
from the vehicle. The transmission will not be capable
of the Automatic Stop/Start function.
When diagnosing and repairing transmission, engine,
or electrical concerns on NSS equipped vehicles, which
may be related to Automatic Stop/Start related
hardware. DTCs related to the Stop/Start system may
still be enabled. Utilize appropriate diagnostics within
SI and replace any needed components as directed. No
changes will occur to Automatic Stop/Start related
components, except as noted.
Page 2
January, 2024
Bulletin No.: 21-NA-132
Version
4
Modified
Released June 09, 2021
Revised October 29, 2021 – Revising to add Cheyenne in the Subject and under
Information and revised information under Considerations for Diagnosing Base Engine or
Electrical Wiring Concerns.
Revised February 10, 2023 — Added the 2022 Model Year.
Revised January 25, 2024 – Added MHS and MHT Transmission RPO’s.
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.
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