TCSC Top Issues This Week
The Techline Customer Support Center (TCSC) is available to help dealerships with diagnostic and programming issues related to Techline Connect (TLC) and the Service Programming System (SPS). TCSC has now […]
Inoperative Sunroof Due to Air Deflector Clips
The sunroof may not be operating properly and/or the sunroof air deflector may not be functioning properly on some 2017-2023 Acadia (Fig. 1); 2018-2023 Enclave, Traverse; and 2024 Enclave and […]
Headlamp Cooling Fan Humming Sound
A humming or buzzing sound may be heard coming from the front of some 2025 Tahoe, Suburban, Yukon and Escalade models. (Fig. 4) The sound may be the headlamp mounting […]
September Service Newsletter from the Experts at GM TAC
The latest diagnostic assistance from the professionals at the GM Technical Assistance Center is now available in the September GM Technical Assistance Center (TAC) Newsletter. It covers a number of […]
Faster Case Response Times in CX Connect
To avoid wait times for technical support in the dealership, prior to contacting the GM Technical Assistance Center (TAC) and Techline Customer Support Center (TCSC) as well as and other […]
Ground Fault at the Transmission Case
Some 2025-2026 Equinox and Terrain models equipped with the VT40 transmission (RPO MRQ) may have a no start condition with DTCs P27EC (Transmission Range Control Valve Position Sensor Circuit Performance) […]
Sunshade Lamp Supply Circuit Draw
Some 2025-2026 Tahoe, Suburban, Yukon and Escalade models may experience a low or dead battery. During battery draw diagnostics, a 550 ma draw may be found, and which can be […]
Transmission Park Lock Valve Parts Released
Park lock valve-related faults on 2020-2025 Corvette models were previously repaired by replacing the transmission assembly (RPO M1L, M1M, MLH). Parts and service procedures are now available for servicing the […]
Automatic Transmission Fluid Appearance and Color
When servicing 8T45/50/60, 9T45/50/60/65 and 6T30/35/40/45 transmissions on 2016-2025 Malibu; 2017-2026 XT5; 2018-2026 Enclave; 2019-2026 Blazer; 2020-2022 Encore; 2020-2025 XT6; 2020-2026 Encore GX, Envista, Equinox, Trax, Acadia; 2021-2026 Envision, Trailblazer; […]
New Firewall Exclusions, Windows 10 Support Removed in Latest Dealer Infrastructure & Security Guidelines Update
The latest GM Dealer Infrastructure & Security Guidelines (DISG) have been updated with recommended firewall exceptions for Techline Connect applications. (Fig. 1) The following exception has been added and needs […]
Incomplete Radio Registration Prevents Owner’s Manual Download
As part of the Pre-Delivery Inspection (PDI) of the 2026 ESCALADE IQ/IQL and VISTIQ, the digital Owner’s Manual should be downloaded to the infotainment system. (Fig. 3) To download the […]
New 12V Battery Ratings Chart for the 2026 Model Year
The latest Original Equipment (OE) Battery Ratings chart for the 2026 model year is now available under the Reference Charts menu for use when testing OE batteries. (Fig. 5) […]
GM Service Know-How Emerging Issues
The monthly GM Service Know-How Emerging Issues seminars provide service/technical information on current issues and GM-certified repairs. This month the seminar highlights 10L1000 transmission valve body repair. (Fig. 8) […]
Enhancing Diagnostic Accuracy with Thermal Imaging — New Essential Tool Shipping to Dealerships
Thermal imaging was once reserved for specialty diagnostics, but it’s now becoming an accessible and valuable tool in dealership service bays. The GM-60503 Thermal Imaging Camera, a new GM Essential […]
EV Reduced Acceleration Conditions
A reduced acceleration message may be displayed along with limited propulsion power under certain operating conditions on some 2022-2026 HUMMER EV, BrightDrop models; 2023-2026 LYRIQ; 2024-2026 Blazer EV, Silverado EV, […]
Incorrect Brake Pedal Position Sensor Signal Input
Some 2012-2019 Cruze; 2012-2020 Regal; and 2012-2025 Malibu, Equinox and Terrain models may experience low or reduced power under acceleration. DTCs P057B (Brake Pedal Position Sensor Performance), P057C (Brake Pedal […]
Serial Data Authentication Configuration After Programming a Control Module
After replacing a module on a GM model equipped with the Vehicle Intelligence Platform (VIP), several possible concerns may occur. These include: Serial Data Authentication Configuration fails to complete. DTC […]
August Service Newsletter from the Experts at GM TAC
The latest diagnostic assistance from the professionals at the GM Technical Assistance Center is now available in the August GM Technical Assistance Center (TAC) Newsletter. It covers a number of […]
Print Edition
Previous Articles
CX Connect Case Creation Tips
New Diagnostic Strategy: Reprogram Control Modules Before Replacement
Corvette Center Console Latch Pushbutton Replacement
New Dash Cover Addresses Windshield Glare
The Info on Dealer Information — Choosing the Right Contact for Service Department Concerns
GM Service Know-How Emerging Issues
Learn More About CX Connect – New System Going Live Soon
Techline Connect & GDS2 Split Update Released
Poor A/C Performance Due to Loss of Refrigerant
Loss of A/C and Warm Air Conditions
July Service Newsletter from the Experts at GM TAC
Power Hood Closure Conditions
Diesel Engine Oil Cooler Seal Leak
Check Grounds for No Start Condition
Battery Cable Clamp Alignment Results in Low Voltage
Upper Body Auxiliary Lamp Connection
Anti-Chip Coating Appearance on Full-Size Trucks
GM Service Know-How Emerging Issues
OneCRM and Dealer Case Management System Migration
DCA-8000
Troubleshooting
Guide
TAC Newsletter September 2025
TAC Newsletter August 2025
Techline Connect Tips November 2024
CX Connect Case Creation Help + Tips and Tricks
