21-NA-033

Bulletin No.:
Service Bulletin
Date:
21-NA-033
November, 2022
INFORMATION
Subject:
Information on Malfunction Indicator Lamp (MIL) Illuminated – Multiple Transmission
DTCs Set
Attention: This bulletin is to advise the technicians of a new transmission service diagnostic test.
This bulletin will become obsolete at a later date.
Note: If DTC P1955 or P0867 is set, please proceed to
the latest version of PIP5797 for direction.
Brand:
Model:
Chevrolet
Corvette
Model Year:
VIN:
from
to
from
to
2020
2023
—
—
Engine:
Transmission:
—
—
Involved Region or Country
North America, Europe, Middle East, Japan, Australia/New Zealand
Condition
Some customers may comment that the MIL is illuminated.
Technicians may find one or more of the following DTCs set in the Transmission Control
Module (TCM):
P0747, P0746, P0777, P0776, P2809, P2808, P2724, P2723, P0797, P0796, P2715,
P2714, P2818, P2817, P08C5, P08C4, P27BA, P27B9, P27C2, P27C1, P27CA, P27C9,
P27D2, P27D1, P282A, P2829, P1956, P1957, P1958, P1959, P2735, P18A8, P18A9,
P2821, P2820, P187D, P187E, P2855, P2853, P2856, P2854, P0869, P0868, C2A18,
C2A19, P0844, P0841, P0849, P0846, P0874, P0871, P0879, P0876, P1946, P1947,
P1948, P1949, P194A, P1961, P194B, P194C, P194D, P194E, P073F, P074A, P074B,
P074C, P074D, P074E, P074F, P07D8, P073E, P194F and/or P1950.
Cause
This condition may be caused by an Internal transmission solenoid or switch sticking due
to debris.
Information
If any of the P-codes are set, perform a transmission service diagnostic test. Refer to
Transmission Service Diagnostic Test in the Service Manual.
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.
Copyright 2022 General Motors LLC. All Rights Reserved.
Page 2
November, 2022
Bulletin No.: 21-NA-033
Version
6
Modified
Released February 12, 2021
Revised June 28, 2021 – Added a Note at beginning of Service Procedure and new GDS
information to steps 8 and 9.
Revised December 07, 2021 – Added a Note under the Subject, the 2022 Model Year,
DTC P1961 to Condition section, updated the Involved Region or Country section and
updated information under step 10 and Parts Information.
Revised December 15, 2021 – Updated the Service Procedure.
Revised July 29, 2022 – Added the 2023 Model Year, Removed P1955 and P0867 from
Condition and Correction sections, Changed And to Or in bold text in Correction section
and Added an Important statement above the Service Procedure.
Revised November 10, 2022 – Added Attention statement, removed Correction section to
add an Information section, removed the Service Procedure, Parts Information and
Warranty Information sections.
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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