23-NA-178

Bulletin No.:
Service Bulletin
Date:
23-NA-178
October, 2023
TECHNICAL
Subject:
Malfunction Indicator Lamp (MIL) Illuminated - Multiple DTCs Set
Brand:
Model:
Chevrolet
Corvette
Model Year:
VIN:
from
to
2023
2023
from
to
Engine:
Transmission:
5.5L (LT6)
M1M
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 Engine Control
Module (ECM):
• U0611
• U0613
• U068A
• U0693
• P010B
• U1319
• U1373
Note: This is a multi-wire bundled harness, and depending on which wire is damaged,
the ECM may set a variety of DTCs.
Cause
This condition may be caused by the engine wiring harness being built slightly out of
position in its plastic channel by the supplier, resulting in a chaffing condition near the left
rear lower control arm attachment.
Copyright 2023 General Motors LLC. All Rights Reserved.
Page 2
October, 2023
Bulletin No.: 23-NA-178
Note: If no contact is found, use regular SI diagnostic procedures to troubleshoot
the DTCs.
If the MIL is on due to a DTC setting in the ECM:
6445155
Correction
1. Hoist vehicle and inspect the engine wiring harness for chaffing as indicated in the
graphic above.
2. Repair the wires. Refer to Wire to Wire Repair in the Service Manual.
6445156
3. Remove the 9 tie straps holding the engine harness in the vertical channel and
reposition the harness up as needed with at least 15 mm (1) of clearance to the
control arm attachment point.
4. Replace tie straps and trim excess strap material.
Bulletin No.: 23-NA-178
October, 2023
Page 3
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.
Warranty Information
For vehicles repaired under warranty, use:
Labor
Operation
5430902
Description
Labor Time
Wire-to-Wire Repair
Use
Published
Labor
Operation
Time
Version
1
Modified
Released October 05, 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.
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