Global Diagnostic System 2 (GDS2) is GM's PC-based diagnostic software. An appropriate vehicle communication interface, such as a supported MDI or MDI 2, connects the computer to the vehicle. Techline Connect is GM's integrated application for service information, programming and scan-tool diagnostics. These names describe different parts of the workshop system rather than interchangeable tools. ACDelco Technical Delivery System; GM Techline Connect user guide.
Diagnostic and programming functions
- GDS2: diagnostic software with vehicle-specific diagnostic data packages.
- MDI / MDI 2: vehicle communication interfaces; verify compatibility with the application and vehicle.
- Tech2Win: PC emulation of the earlier Tech 2; separate from GDS2.
- Service Programming System (SPS): the programming workflow; access, calibration availability and security provisions vary.
See the GM ACDelco portal and Techline Connect user guide.
Vehicle coverage
GM's GDS2 vehicle chart shows a model-by-model transition with overlap; for example, its 2010 list includes the Saab 9-5. The Opel/Vauxhall matrix likewise identifies GDS2, Tech2/Tech2Win and Opel/Vauxhall Diagbox by model. A model year alone is not enough to establish coverage, especially across brands and regions.
See GM Tech 2 diagnostic tool, Opel diagnostic systems, and Saab diagnostic systems.
American Honda also specifies MDI 2 and Techline Connect for the 2024 Honda Prologue and Acura ZDX; see Honda and Acura HDS diagnostics. American Honda compatible interfaces.
Isuzu IDSS exception for Chevrolet low-cab-forward
GM's November 2025 North American bulletin PIT6453 states that the Chevrolet low-cab-forward models it lists are no longer supported by Techline Connect GDS2 or SPS; dealers are directed to Isuzu IDSS, which the bulletin says works with the existing MDI2. This applies to the listed vehicles and is not a change to every Chevrolet model. GM bulletin PIT6453. See Isuzu diagnostic systems.
Model and year coverage examples
| Manufacturer | Model / model year | Documented tool selection |
|---|---|---|
| GM / Saab | Saab 9-5, MY2010 | GM’s GDS2 chart lists this application; Saab’s own MY2010 first-generation 9-5 procedure still names Tech 2, so read the model-specific procedure and generation carefully. |
| Honda / Acura | Honda Prologue and Acura ZDX, MY2024 | American Honda lists GM MDI2 and GM Techline Connect for these vehicles, a documented GM-platform overlap. |
| Chevrolet / Isuzu | Specified North American Chevrolet low-cab-forward models in GM bulletin PIT6453 (2025) | GM directs these listed applications to Isuzu IDSS using MDI2; they are exceptions to the ordinary GDS2/SPS workflow. |
| Opel / Vauxhall | Model-specific legacy applications, including Meriva B from MY14.5 and Antara from MY2011 | The official matrix separately lists GDS2/SPS, Tech2/Tech2Win and Opel/Vauxhall DiagBox. See the vehicle matrix summary. |
Sources: GM GDS2 supported vehicle chart; American Honda interface list; Opel/Vauxhall matrix; GM bulletin PIT6453, linked in the Isuzu coverage section above.