GM Service Update: Telematics Module Reprogramming for Silverado EV & Sierra EV
GM has issued a new service update that affects certain 2025–2026 Chevrolet Silverado EV and GMC Sierra EV models. While this isn’t a recall, it’s an important software-related update that owners should be aware of—especially given how critical connectivity systems are in modern EVs.
What’s the Issue?
According to GM, some vehicles may experience a condition where the Telematic Control Module (TCM) could enter an unrecoverable state.
This module is responsible for key connected services, including:
- OnStar functionality
- Vehicle connectivity and remote features
- Over-the-air (OTA) update capability
If the module enters this unrecoverable state, it could impact connectivity features or prevent proper communication with GM’s systems.
What GM Is Doing
GM’s fix is to reprogram the Telematic Control Module with updated software.
In many cases, this update may happen automatically via over-the-air (OTA) updates, meaning you may not need to visit a dealer at all.
However, if OTA is not completed successfully, the update can be performed at a dealership.
Important Detail: Multiple Updates May Be Required
One key detail in this bulletin is that the module may be several software versions behind.
That means:
- The update process may require multiple programming cycles
- Technicians must continue updating until the system confirms it has reached the latest software version
This is not a quick “one-and-done” update in every case as it may take multiple passes to fully bring the module up to date.
How Dealers Verify the Fix
GM specifies that the update is only considered complete when the system displays the same calibration screen, confirming the module is fully updated to the latest level.
Additionally, technicians will:
- Verify connectivity by placing a test OnStar call
- Ensure the module is properly configured and activated
- Clear any diagnostic trouble codes (DTCs) after programming
What Owners Should Know
This is classified as a service update, not a recall. That means:
- You likely won’t be asked to make a special trip to the dealer
- The update will typically be performed during a routine service visit
- Some vehicles may already receive the fix via OTA
GM also notes that dealers are instructed to complete this update on any affected vehicle in inventory before it is delivered to a customer.
EV Outdoors Take
This is a good example of how software stability is just as important as hardware in modern EV trucks.
The telematics module sits at the center of your truck’s connected experience—from remote commands to OTA updates—so keeping it fully updated is critical.
The fact that GM is addressing this through both OTA updates and dealer programming shows how these vehicles are increasingly software-defined.
For Silverado EV and Sierra EV owners, this is a low-drama, high-importance update—not something to worry about, but definitely something you want completed.
What You Should Do
- Keep your vehicle connected to receive OTA updates
- Ask your dealer to check for open service updates at your next visit
- Ask your dealer to perform vehicle wide programming (VWP) if you take it in for service. This will update all module software and is covered under GM warranty for EVs.
Staying current on updates like this helps ensure your truck continues to perform reliably and as designed day-to-day.
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