NHTSA ID Number: 10249034
Manufacturer Communication Number: 21-NA-155
TSB/Document Date: 2024-01-19
Summary
This informational bulletin advises the technician to check for faults that may be caused by the trailer otherwise found by a possible faulty trailer connector.
Bulletin No.:
Service Bulletin
Date:
21-NA-155
January, 2024
INFORMATION
Subject:
Information on Check Trailer Wiring Message and/or Service Trailer Brake Displayed
on Driver Information Center (DIC) - DTC C1114 Set
Brand:
Model:
to
Escalade Models
2021
2024
Silverado 1500 (New
Model)
2019
2019
Silverado 1500
2020
2021
2022
2022
Silverado 1500
2023
2024
Silverado 2500HD/
3500HD
2020
2024
2021
2024
Sierra 1500 (New
Model)
2019
2019
Sierra 1500
2020
2021
2022
2022
Sierra 1500
2023
2024
Sierra 2500HD/
3500HD
2020
2024
Yukon Models
2021
2024
Silverado 1500 - LTD
(RPO J21, VIN Digit
5 = W / Y)
Chevrolet
Silverado 1500 - New
(RPO J22, VIN Digit
5 = A / D)
Suburban
Tahoe
Sierra 1500 - Limited
(RPO J21, VIN Digit
5 = 8 / 9)
GMC
Model Year:
from
Sierra 1500 - New
(RPO J22, VIN Digit
5 = H / U)
VIN:
from
to
Engine:
Involved Region or Country
North America, Middle East, Chile (West), Thailand (ASEAN), Paraguay
Additional Options (RPOs)
JL1 (CONTROL-INTEGRATED TRAILER BRAKE)
Condition
Some customers may comment on one or more of the following messages displayed on
the DIC:
• Check Trailer Wiring
• Service Trailer Brake
Some technicians may find DTC C1114 set on vehicles equipped with an Integrated
Trailer Brake Controller.
Copyright 2024 General Motors LLC. All Rights Reserved.
Page 2
January, 2024
Bulletin No.: 21-NA-155
Note: The below two possible causes can also affect a truck equipped with an
aftermarket trailer brake controller
Cause
This condition may be caused by a poor connection at the 7-way trailer connector at the
vehicle and/or trailer side of the connector.
– Trailer Side Connector (Plug) - There are several manufacturers of 7-way (trailer side)
connectors and many do not comply with the SAE standard specifications. Some
7-way (trailer side) connector plugs may not properly engage the truck's 7-way
connector socket and cause open circuits. Since the Trailer Brake Control Module is
always monitoring the vehicle and trailer circuits/components, a poor connection at the
7-way connector can cause a “Check Trailer Wiring” message on the DIC. This may
also cause deformation and excessive wear of the terminals on the truck's 7-way
connector socket. Over time, this will lead to poor terminal tension between the 7-way
(trailer side) connector plug and the truck's 7-way connector socket.
7-Way Trailer Connector:
– The 7-Way Trailer Side Connector (Plug) - Engineering has recommended the use of
Pollak Heavy Duty 7-Way (Trailer Side) Connector Plugs. Pollak is the OEM
manufacturer of the truck's 7-way connector socket; and by using a Pollak Heavy Duty
7-Way (Trailer Side) Connector Plug, this will ensure proper fit when the two
connectors are mated. Pollak's website is: www.pollakaftermarket.com. Once at the
home page select "Connectors" then "Heavy Duty 7-Way Plugs and Accessories" and
then " RV Connectors Heavy Duty & Adaptors" (example 12-706, 12-702).
Note: If the truck's 7-way connector socket terminals are deformed or have excessive
wear, it will be necessary to replace the truck side connector, see info below, along with
the trailer's 7-way connector plug to a Pollak HD.
Information
• Truck Side Connector (Socket) - If the truck's 7-way trailer connector socket terminals
are deformed, have excessive wear, door/cover not holding trailer connector plug
securely, etc. it will be necessary to replace the truck side trailer connector socket with
updated GM part number 84056018.
Trailer Side Customer Recommendation:
1. Inspect and clean the ground wire (normally white wire) connection on the trailer
side of the 7-pin connector.
2. Make sure that the wires inside the trailer side connector are clean and securely
fastened.
3. If an electrical junction box exists on the trailer, make sure the wires inside the
junction box are clean and securely fastened.
4. Inspect Trailer Grounds for potential issues.
Note: Trailer System issues should not be covered under the GM Bumper-to-bumper
warranty.
Customer Trailer Recommendation:
Refer to bulletin : Information On Common Customer Trailer Side Faults to print the
procedure that can be used to help the customer understand any trailer related issues.
Note: Trailer side system issues should not be covered under the GM
Bumper-to-bumper warranty.
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.
Bulletin No.: 21-NA-155
January, 2024
Page 3
The Following Failures are the Result of
Trailer Side Connection Issues - Non
Warranty Issue
⇒ When diagnosing trailer message issues without
the trailer present, please refer to Document ID:
5627183: PIT5509G: Diagnostic Tip - Check and/or
Service Trailer Brake System message DTC C1114
The Following failures are the result of trailer side
connection issues:
5867995
3. Trailer side connector is damaged/deformed
causing removal of protective plating. This is the
result of the trailer side connector is moving or
bouncing when connected (excessively worn
connector) – Non-Warranty Issue.
5867917
1. Short on trailer side damaged the terminal – Trailer
side connector is loose/worn – Non-Warranty
Issue.
5867997
4. Trailer side harness retention tab has been broken
off cover which is the result of customer pulling
away from trailer without releasing the trailer
harness – Non-Warranty Issue.
5867994
2. The blue/green is expected, and this small amount
of corrosion does not impact function of connector
– Non-Warranty Issue.
Page 4
January, 2024
The Following Failures are the Result of
Vehicle Side Connection Issues Subject to Terms of Warranty
Bulletin No.: 21-NA-155
Parts Information
Causal
Part
N/A
Description
84056018
Part
Number
Truck 7-way
Trailer
Connector
Socket
Qty
1
Warranty Information
For trailer related issues: No warranty labor operation is
provided for concerns related to the trailer.
For Truck 7-Way Connector Replacement use: 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.
5867998
1. Sealant from part on terminals, would cause
intermittent connection issues connecting to trailer
– Subject to terms of warranty.
5868000
2. Terminal is pushed out – Subject to terms of
warranty.
Labor Operation
Description
Labor Time
5486198*
Tow Vehicle Electrical Receptacle Diagnostic
0.3 hr
Add
Tow Vehicle Electrical Receptacle Replacement
0.2 hr
*This is a unique Labor Operation for Bulletin use only.
Bulletin No.: 21-NA-155
January, 2024
Page 5
Version
3
Modified
Released September 21, 2021
Revised June 14, 2022 - Added 2022 to Model Year and Updated Information section.
Revised January 11, 2024 - Added the 2023 — 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.
WE SUPPORT VOLUNTARY
TECHNICIAN
CERTIFICATION
- Oiojuct heat shrink wire connectors are durable and...
- Easy and Reliable Connection: The wire connector kit...
- Versatile Application: An electrical connectors kit is...
- Secure and Waterproof: The heat shrink crimp connectors...
- Convenient Assortment: The set includes a range of connector...
- [PREMIUM QUALITY] Thick copper barrel ensures strong secure...
- [DURABILITY] Each butt, ring and fork terminal features a...
- [WATERPROOF] Insulation tubing has unique dual-walled...
- [WIDE APPLICATIONS] Compliant with all electrical standards...
- [TYPE and SIZE] The connector assortment includes red, blue...
Last update on 2026-06-23 / Affiliate links / Images from Amazon Product Advertising API
If the PDF is very large, it may not load in the preview below.
Some older TSBs had multiple PDFs — visit the NHTSA Website to view all PDFs.
If the TSB PDF does not show, download or view it on the NHTSA Website.
Click on the (+) Plus Sign
Then Click on Associated Document(s)
Search NHTSA Database for Recalls
Search NHTSA Database for Vehicle Investigations
View Latest Vehicle Investigations
Search NHTSA Database for Vehicle Complaints
View Latest Vehicle Complaints
TSB/Document ID: 21-NA-155
Replacement Service Bulletin Number:
MFR Communication Date: 2024-01-11
MFR Internal Campaign ID/Software Version:
Communication Type: Service Bulletin/Repair Instructions
NHTSA Components: ELECTRICAL SYSTEM
MFR Component System:
MFR Component Subsystem:
Previous TSB | Next TSB |
- [Notice] When you receive a used device, it may be a customer return resold by Amazon without inspection. You can exchange it for a new one through Amazon. As this situation is unavoidable, we sincerely apologize. For any issues, contacting us via Amazon's "Messages" is the best way. THINKSCAN 689BT Bidirectional Scan Tool Can Be Used Immediately After It is Turned On, Without Complicated Registration Process, Which is More Convenient & Quick.
- Full Bi-Directional Control & 3000+ Active Tests: Take control and test components like actuators, fuel injectors, relays, and cooling fans in real time. You’ll quickly see if the problem is in the part itself or the control module — saving you hours of guesswork and frustrating trial-and-error.
- Advanced ECU Coding Capabilities: Handle module matching and hidden feature activation with confidence. When you replace an ECU or want to customize settings, this obd2 scanner diagnostic bi directional tool gives you the professional-level capabilities you need without the dealership price tag.
- 34+ Useful Reset and Maintenance Functions: Complete everyday service tasks smoothly with a wide range of helpful reset and maintenance functions. Whether you’re keeping up with regular upkeep or tackling a specific job, this scanner makes maintenance simpler and less stressful for both DIYers and pros.
- Comprehensive Full System Diagnostics: Diagnose every major system — Engine, Transmission, ABS
, SRS, TPMS, and more — all in one place. Finally stop wondering if you’re missing something important; get the full picture and clear codes with ease.
Last update on 2026-07-02 / Affiliate links / Images from Amazon Product Advertising API
- Top Reasons to Choose the D7S OBD2 Scanner: XTOOL D7S car scan tool, an upgrade of XTOOL D7, offers comprehensive features for automotive technicians, workshops, and DIY enthusiasts 1. Upgraded Hardware: 2+64GB memory, rear camera, intuitive interface, foldable bracket 2. Complete Diagnostics: FCA Autoauth, OE-level all system scan, 39+ maintenance services, 4K+ bidirectional, CANFD/DoIP protocol 3. Advanced Capabilities: ECU c0ding, PMI functions 4. Wide Compatibility: Support 10,000+ models, covering 99% vehicle brands 5. Multi-language: Available in 22+ languages, No IP Restrictions 6. 3-Year Updates: Save 300 bucks on software updates for the latest features and optimizations
- 2026 Upgraded D7S Car Scanner Features: The newly 2026 D7S V2.0 scanner for car brings exciting features for advanced vehicle diagnostics and enhanced user experience 1. FCA AutoAuth: Now supports FCA SGW module for Chrysler, for Jeep, for Dodge (2018+), for Fiat (2017+), enabling faster vehicle communication without gateway restrictions 2. PMI (Offline ECU Pr0gramming): Allows for Ford, for Lincoln, and for Mazda ECU pr0gramming for new modules 3. Optimized Diagnostic Report 2.0: Personalized reports with logos and customer info for auto shops. Note: Compatibility varies by cars, please check before order
- 39+ Services/Resets/Adaptations/Relearns/Calibrations: XTOOL D7S full system car scanner diagnostic tool tackles 99% of common car issues through its 36+ special functions, including Oil Reset, EPB, SAS, BMS, Throttle Reset, Injector C0ding, ABS Bleed, TPMS Reset, Power Balance, etc and also covers specific-vehicle functions like Crank Sensor Relearn, ABS Initialization, Cylinder Power Balance, Fuel Trim Reset, Idle Relearn etc. This car diagnostic scanner enhances efficiency, making repairs and maintenance hassle-free. Tip: DO NOT for All vehicles, please check compatibility first
- Cost-effective ECU C0ding Scan Tool for Specific Brands: Enhance your vehicle's performance with XTOOL D7S! This obd2 scanner all systems bidirectional offers advanced capabilities at an affordable price, supports online for BMW, for Benz and offline for BENZ, for MIT, along with PMI functions for Ford, for Mazda, and for Lincoln. Ideal for technicians and DIY enthusiasts, this automotive scanner diagnostic tool optimizes vehicle performance and enhances the driving experience. Note: Not for all cars and modules, please send car VIN to check the compatibility before purchase
- OE All System Diagnostic & 8 Pids Graphing: XTOOL D7S is a comprehensive all system bi directional obd2 scanner that delivers dealer-level diagnostics, completely controlling over your vehicle’s performance and health. This automotive scan tool can read and clear DTCs, view live data and ECU information, retrieve freeze frames, and perform active tests and full obd2 functions. This bi-directional scan tool can can identify your vehicle's make, model, and year information with just one click and show up to 8 PIDs live data with options for CSV viewing, playback, and recording for in-depth analysis. It is easy-to-use for both professionals and beginners, helping pinpoint issues efficiently
Last update on 2026-06-30 / Affiliate links / Images from Amazon Product Advertising API
- 【✅Compared to BOSSCOMM IF742, IF745 Offers Full-System Diagnostics】The BOSSCOMM IF745 car diagnostic scanner is an upgraded model of IF742. In addition to supporting all OBD2 Code Reader functions and 6 reset options (ABS/EPB/SAS/BMS/Oil/Throttle), it expands diagnostics from 4 systems (Check Engine/ABS/SRS/Transmission) to vehicle All systems, including Steering, Suspension, and Body Electronics. This provides deeper, more comprehensive diagnostic capabilities.
- 【✨10 OBD2 Functions】The BOSSCOMM IF745 scan tool’s DTC Lookup instantly translates fault codes into user-friendly explanations, its I/M Readiness feature streamlines emissions testing with a single tap, and Freeze Frame lets you pinpoint the exact moment of a fault for in-depth root-cause diagnosis. Combined with a live data dashboard and advanced diagnostics (O2S, OBMon, EVAP), it delivers comprehensive insights for confident troubleshooting.
- 【✨Deep Diagnostics for All Vehicle System Modules】Beyond code reading/clearing and ECU information retrieval, our all-in-one data stream feature lets you inspect all current fault codes and their locations across the vehicle’s systems. This vehicle code reader helps you turn off dashboard warning lights and perform a comprehensive self-check of your car at home—no more back-and-forth trips to the repair shop or hefty inspection fees.
- 【✨6 Essential Resets: ABS Bleeding, Oil, EPB, SAS, Throttle, BMS】The BOSSCOMM IF745 obd2 scanner diagnostic tool swiftly purges air from brake lines to restore braking sensitivity, fine-tunes maintenance cycles to eliminate false alerts, resolves parking brake issues with one-click control, recalibrates steering sensors for stability, optimizes engine idling/acceleration for smoother performance, and deeply resets battery systems to extend lifespan and range via precise parameter adjustments.❗NOTE: Does NOT support bidirectional control, coding, or programming.
- 【✨10,000+ Car Models, AutoVIN, 13 Languages】The BOSSCOMM IF745 vehicle scanner diagnostic tool covers 73+ global car brands and offers support in 13 languages, making it perfect for DIYers, auto mechanics, or as a thoughtful gift. With a single-click AutoVIN feature, it instantly retrieves vehicle serial numbers, streamlining diagnostics for users globally. This adaptable tool balances user-friendliness with precision, catering to both personal and professional requirements.✅Unsure about compatibility? Compatibility will vary on vehicles' model and year, pls reach us via 📧 [email protected] 📧 before purchase.
Last update on 2026-07-02 / Affiliate links / Images from Amazon Product Advertising API
This product presentation was made with AAWP plugin.