23-NA-171

Bulletin No.:
Service Bulletin
Date:
23-NA-171
October, 2023
INFORMATION
Subject:
Camshaft Position Learned Values Reset Not Available – ECM Replacement Required
Brand:
Model:
Chevrolet
Corvette
Model Year:
VIN:
from
to
from
to
2023
2023
—
—
Engine:
Transmission:
5.5L (LT6)
—
Involved Region or Country
United States, Canada, Europe, Middle East, Australia/New Zealand
Condition
Technicians may find that for the 2023 Corvette engine RPO LT6, the Camshaft Position
Learned Values Reset function is not compatible with the current ECM base software.
– This reset function is used to reset the camshaft position adaptation values in the event
of a mechanical timing or sensing component replacement.
Cause
This condition may be caused by the ECM base software not being compatible with the
Camshaft Position Learned Values Reset function.
Correction
Any time one of the following components is replaced, the ECM must also be replaced in
order to perform the “Camshaft Position Learned Values Reset” function.
This procedure is required when the following component has been repaired, replaced,
removed, or serviced:
• B23 Camshaft Position Sensor
• B26 Crankshaft Position Sensor
• Any repair that disturbs the alignment between the components: Camshaft &
Crankshaft
• Camshaft
• Camshaft Sprocket • Crankshaft
• Engine Assembly
• Timing Chain
Copyright 2023 General Motors LLC. All Rights Reserved.
Page 2
October, 2023
Bulletin No.: 23-NA-171
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.
Service Procedure
Refer to Engine Control Module Replacement in SI.
Parts Information
Causal
Part
X
Description
Engine Control
Module
Part
Number
Qty
12731739
1
Warranty Information
For vehicles repaired under the Powertrain coverage,
use the following labor operation. Reference the
Applicable Warranties section of Investigate Vehicle
History (IVH) for coverage information.
Labor
Operation
4089158*
Description
Labor Time
Engine Control Module
Replacement
1.5 hrs
*This is a unique Labor Operation for bulletin use only.
Version
1
Modified
Released September 26, 2023
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