Archive for September, 2025

Inoperative Sunroof Due to Air Deflector Clips

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 […]

September 30, 2025 —
Headlamp Cooling Fan Humming Sound

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 30, 2025 —
September Service Newsletter from the Experts at GM TAC

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 […]

September 30, 2025 —
Faster Case Response Times in CX Connect

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 […]

September 26, 2025 —
Ground Fault at the Transmission Case

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) […]

September 26, 2025 —
Sunshade Lamp Supply Circuit Draw

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 […]

September 26, 2025 —
Transmission Park Lock Valve Parts Released

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 […]

September 26, 2025 —
Automatic Transmission Fluid Appearance and Color

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; […]

September 26, 2025 —
New Firewall Exclusions, Windows 10 Support Removed in Latest Dealer Infrastructure & Security Guidelines Update

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 […]

September 18, 2025 —
Incomplete Radio Registration Prevents Owner’s Manual Download

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 […]

September 18, 2025 —
New 12V Battery Ratings Chart for the 2026 Model Year

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)   […]

September 18, 2025 —
GM Service Know-How Emerging Issues

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)   […]

September 18, 2025 —