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 […]
Diagnostic Tips for Audio and Display Screen Concerns on IOK Radios
There may be several display screen concerns and other conditions on the infotainment system (RPO IOK) of some 2022-2025 Silverado, Tahoe, Suburban, Sierra, Yukon, HUMMER EV; 2024-2025 Corvette, Silverado HD […]
Required Information for Restricted IOK Radios
The infotainment system (RPO IOK) on 2022-2025 Silverado, Tahoe, Suburban, Sierra, Yukon, HUMMER EV; 2024-2025 Corvette, Silverado HD and Sierra HD models is on restriction. (Fig. 3) If the radio […]
Power Doors OTA Update Released for 2025 Escalade
2025 Escalade, Escalade ESV and Escalade V-Series models built early in the model year offered a power-assist exterior door system (RPO APD with R6W) that has power-assisted door opening and […]
QR Code Scanning Helps Avoid Input Mistakes When Programming Modules
When replacing a valve body or transmission on a GM vehicle, it is essential to gather Mechanical Characterization & Virtual Matching (MCVM) data from the cloud. Due to manufacturing variations, […]
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 previews the 2025 Corvette ZR1. (Fig. 12) Fig. […]
New TAC Response Requested Process
A new GM Technical Assistance Center (TAC) process is being implemented to ensure the customer is being considered when TAC is working in partnership with dealership technicians to repair customers’ […]
Keep Your Cool — Air Conditioning Refrigerant Leak Diagnostic Tips
All current GM vehicles are manufactured with fluorescent dye installed in the air conditioning refrigerant system. The dye mixes and flows with the A/C compressor oil to help in locating […]
Water Leak at the A-Pillar Body Plug
There may be several inoperative electrical features on some 2019-2025 Blazers. (Fig. 4) These conditions may include inoperative door chimes and door lamps, inoperative power mirrors or a distorted driver-side […]
Unlatching the Front Compartment Hood with a Weak 12V Battery
The front compartment hood on some 2024-2025 Corvette models may not fully unlatch when one of the hood release buttons is pressed if the 12V battery is weak, resulting in […]
Differences in Approach Lighting on Mid-Size SUVs
The approach lighting on the 2024-2025 Traverse and Acadia has several differences compared to the lighting elements on the 2025 Enclave. It’s important to understand these differences when diagnosing any […]
April 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 April GM Technical Assistance Center (TAC) Newsletter. It covers a number of […]
Outside Rearview Mirror Glass Removal
There are several GM Accessories available that update the design and functionality of the outside rearview mirrors on 2022-2025 HUMMER EV models. (Fig. 1) GM Accessories range from different housing […]
Executive Second-Row Seat Operation
The available Executive Second-Row Seats (RPO ABV, AL4) in the 2025 ESCALADE IQ (Fig. 5) feature power operation for second-row passengers, which makes it easy to adjust the seats for […]
Super Cruise Disengages or is Unavailable
The Super Cruise driver assistance technology may disengage or be unavailable on some 2021-2025 Escalade; 2023-2025 LYRIQ; 2024-2025 Traverse, Acadia; 2025 Enclave, CT5, ESCALADE IQ, OPTIQ, Blazer EV, Equinox EV, […]
2025 Cadillac VISTIQ TAC Action Center
The GM Technical Assistance Center (TAC) has established a TAC Action Center for U.S. dealerships to provide product feedback on the all-new 2026 Cadillac VISTIQ. (Fig. 14) Fig. 14 […]
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 takes a look at trailer lighting and braking operation. […]
Dealer Case Management Tips for TCSC Submissions
Technicians can use Dealer Case Management (DCM) to create, view and update Techline cases in real time with the Techline Customer Support Center (TCSC), reducing the time spent waiting on […]
EVAP System on the New 1.2L Engine Requires Updated Leak Test Diagnostics
The 2025 Envista, Encore GX, Trax and Trailblazer are available with the new 1.2L engine (RPO LBP). The engine configuration features E85 compatibility, which required an update to the Evaporative […]
NACS Charging Adapters Designed for Public DC Chargers Only
The North American Charging Standard (NACS) DC adapters (Tesla Supercharger adapters) (Fig. 11) that are available from GM are for use on public DC Fast Charging stations only. Fig. […]
New Feedback Process on Shipping Parts to the Warranty Parts Center
The GM Warranty Parts Center (WPC) requests the return of specific parts replaced at dealerships through the Global Warranty Management (GWM) system to better understand and help resolve product issues […]
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Previous Articles
FSE Technician Recognition Awards – 1st Quarter 2025
March Service Newsletter from the Experts at GM TAC
GDS2 Core Update Required by March 16
MDI 2 Order Lead Times Update
Low Oil Pressure at Idle
DTCs Set Due to Wiring Harness Condition
Heavy Fuel Use Message
GM Service Know-How Emerging Issues
Vehicle-Wide Programming Update Shows New Programming Status Summaries
Windshield Wiper Arms Interference
Roof Panel Pop Sound
Guidelines for Successful Installation of GM Accessories
Creating a TAC Case on DCT Transmissions
February Service Newsletter from the Experts at GM TAC
GM Dealer Equipment (GMDE)
TAC Newsletter April 2025
TAC Newsletter March 2025
Techline Connect Tips November 2024
DCM Case Submission & Best Practices Guide
