20-NA-121

Bulletin No.:
Service Bulletin
Date:
20-NA-121
March, 2024
TECHNICAL
Subject:
Water Leak at Roof Area, Various Electrical Issues, No Start, Stall, Brake Lamp Not Off,
Radio Inoperative, Remote Key Inoperative, TPM Light Illuminated, Malfunction
Indicator Lamp (MIL) Illuminated with Possible DTCs C0750 SYM29, C0755 SYM29,
C0760 SYM29, C0765 SYM29
Brand:
Model:
Buick
Chevrolet
Model Year:
from
to
Encore GX
2020
2024
Trailblazer (VIN M)
2021
2024
VIN:
from
to
—
—
Engine:
Transmission:
All
All
All
All
Involved Region or Country
North America
Condition
Some customers may comment on one or more of the following conditions:
• Water leak in the front and/or rear of the vehicle (water found under A-pillar and
B-pillar trim or in the spare tire area).
• Various electrical concerns
• No Start/Vehicle Stall
• Brake lamps will not shut off
• Radio inoperative
• Remote key inoperative
• Tire Pressure Monitor (TPM) light illuminated
• Malfunction Indicator Lamp illuminated
Note: Possible DTCs found, but not limited to: C0750 SYM29, C0755 SYM29, C0760
SYM29, C0765 SYM29
Copyright 2024 General Motors LLC. All Rights Reserved.
Page 2
March, 2024
Bulletin No.: 20-NA-121
5703536
Cause
5703537
Bulletin No.: 20-NA-121
March, 2024
Page 3
5703539
5613596
The cause of the condition may be a pin hole in the roof body seam welding/sealing.
Page 4
March, 2024
Bulletin No.: 20-NA-121
Correction
5615611
Inspect for a leak and repair as necessary.
Service Procedure
5613597
5703542
Note: Water leaks in the rear of vehicle were root
caused to one large leak at driver side, rear upper
liftgate area. The math file below shows the location of
the leak, and the photo shows a view from the
underside of the roof.
Bulletin No.: 20-NA-121
March, 2024
Page 5
5912861
Once the damage is repaired, apply seam sealer along
the roof to body seam to correct the condition.
Inspect and Clean Body-IP Inline
Connectors and Seat Belt Retractor
Pretensioners
5912862
Inspect and repair water leak as necessary.
If you encounter a vehicle with the above conditions,
you must also include an inspection of the connectors
in the water path. Inspect both the A and B-pillar interior
trim and in-line connectors under the instrument panel
(IP) for signs of a water leak at front roof and the rear
cargo interior trim, headliner, and spare tire area for
signs of a water leak at rear roof.
Once the water leak is found, repair any damage that
may have been done due to the water leak.
5752326
Page 6
March, 2024
5703541
Bulletin No.: 20-NA-121
5752327
(#8) — X204 Instrument Panel Harness to Body
Harness, 76-way connector right side
(#11) — F112D Seat Belt Retractor Pretensioner
- Driver
(#6) — X202 Instrument Panel Harness to Body
Harness, 2-way connector left side
(#4) — F112P Seat Belt Retractor Pretensioner
– Passenger (not shown)
(#7) — X200 Instrument Panel Harness to Body
Harness, 76-way connector left side
Clean the water inside of the connector and apply
NYOGEL on terminals for waterproofing.
1. With vehicle off, disconnect the battery.
2. To access the connectors, remove the left and right
garnish trim. Refer to Front Side Door Sill Garnish
Molding Replacement and Center Pillar Lower Trim
Panel Replacement in SI.
3. Inspect the connectors for any moisture. If needed,
clean using a clean nylon bristle brush and dry
connector using compressed air.
4. Preparing NYOGEL 760G (electrical grease) and
flatting tool, apply on IP harness inline connector
surface. Make sure all terminal pins are covered
enough by grease.
5. Reattach the connectors. Make sure the 2nd
locking tab is closed.
6. Reinstall the garnish trim. Refer to Front Side Door
Sill Garnish Molding Replacement and Center
Pillar Lower Trim Panel Replacement in SI.
Bulletin No.: 20-NA-121
March, 2024
Page 7
Parts Information
Causal Part
N/A
Description
Part Number
NYOGEL 760G
(electrical grease)
Qty
Contact Information
1
TAI Lubricants, Inc.
PO Box 1579
Hockessin, DE 19707
Tel: 1-302-326-0200
Fax: 1-302-326-0400
sales@TAI- Lubricants.com or visit
www.tai-lubricants.com
760G
Causal
Part
Description
Part
Number
Qty
N/A
Kent® High-Tech
Seam Sealer
Clear
P10200
1
18920104
(892.0104 in
Canada)
1
Warranty Information
For vehicles repaired under the Bumper-to-Bumper
coverage (Canada Base Warranty coverage), use the
following labor operation. Reference the Applicable
Warranties section of Investigate Vehicle History (IVH)
for coverage information.
Or
N/A
Wurth Euroseal
Gel Clear
Labor
Operation
Description
Labor Time
1481498*
Inspect/Clean Body-IP Inline
Connectors, Seat Belt
Retractor Pretensioners and
Body Joint Resealing
1.2 hrs
*This is a unique Labor Operation for bulletin use only.
For consequential damage, use the labor operation
associated with this bulletin. All parts and labor associated
should be claimed on the same transaction, using OLH as
necessary to cover the labor for repair/replacement of the
subsequently damaged part(s). Refer to Service Bulletin
#18-NA-146 for additional information.
Version
6
Modified
Released June 03, 2020
Revised January 20, 2021 – Added the 2021 Model Year to Encore GX and updated
information to inspect the entire roof, not just the rear.
Revised March 05, 2021 – Added the Inspect and Clean Body-IP Inline Connectors and
Seat Belt Retractor Pretensioners section and updated the Parts and Warranty
Information.
Revised May 20, 2021 – Updated the Subject and Condition section to include DTCs and
other possible conditions.
Revised October 22, 2021 – Added 2022 Model Year, also a Note and Graphics were
added to the Service Procedure designating a newly found water leak location at the
driver side roof/liftgate area.
Revised February 27, 2024 – Added 2023 and 2024 Model Years.
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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