2016-2024 GM OnStar Module Failure: Battery Drain, TSBs, and Programming Secrets
Diagnosing and replacing the Telematics Control Module in your GMC Acadia, Buick Enclave, Chevy Traverse, Express, or GMC Savana without getting stuck with a part that won't work.
- This module MUST be programmed by a dealer or specialist; it is not plug-and-play.
- A used module cannot be programmed by a dealer due to its locked VIN. It requires a specialist with engineering-level tools to 'virginize' it first.
- The most common failure symptom is a parasitic battery drain that kills the battery in a few days, as documented in TSB 16-NA-227.
- For 2017 GMC Acadias, this part only fits the 'Limited' (1st Gen) model, not the redesigned 2nd Gen model.
Symptoms of a Failing OnStar Module
A bad OnStar module can cause some of the most confusing and frustrating electrical problems. Because it's designed to be active even when the car is off, its failure modes are often mistaken for other issues.
1. Parasitic Battery Drain (The Most Common Symptom)
The most notorious sign of a failing OnStar module is a dead battery after the vehicle sits for a few days. The module can fail to enter its 'sleep' mode, causing a constant power draw that drains the battery. GM has issued technical service bulletins (TSBs) for this exact issue, where a faulty module can draw around 380mA continuously. In some cases, this drain is triggered by a specific sequence, like ending a Bluetooth phone call right as you exit the vehicle. If your battery keeps dying for no apparent reason, the OnStar module is a primary suspect.
🎬 Watch: How to diagnose and fix this overnight battery drain.2. 'Service OnStar' Message or Red OnStar Light
The most direct symptom is a message on the driver information center (DIC) that says "Service OnStar" or when the small LED light on the rearview mirror is red or off completely. A green light (solid or flashing) indicates normal operation, while a red or unlit LED points to a system fault or inability to connect to the cellular network.
3. Loss of OnStar Functions and App Connectivity
If you can no longer connect to your vehicle with the mobile app (e.g., for remote start or to check vehicle status), it's a strong sign the telematics module has failed. You will also lose access to in-vehicle services like emergency calling, turn-by-turn navigation (if equipped), and the Wi-Fi hotspot.
4. Associated OBD-II Trouble Codes
A scan tool may reveal specific Diagnostic Trouble Codes (DTCs) related to the module. Common codes include:
- B101D: Electronic Control Unit Hardware
- U1008 & B1B2F: Loss of communication with the radio or other modules on the network.
- P262B: Control Module Power Off Timer Performance
Important: This module has its own internal, non-rechargeable backup battery. Disconnecting the main vehicle battery or pulling the OnStar fuse while the ignition is on can permanently damage this backup battery, requiring module replacement. Always ensure the ignition is fully OFF and retained accessory power has timed out before disconnecting power.
Known Issues, TSBs, and Recalls
GM has released several Technical Service Bulletins (TSBs) related to this module and its tendency to cause battery drain.
TSB 16-NA-227: Dead Battery After Exiting with Bluetooth Active
This bulletin specifically applies to 2016-2017 GMC Acadia, Buick Enclave, and Chevrolet Traverse models. It addresses a condition where the OnStar module stays awake if the driver exits the vehicle while on a Bluetooth call, leading to a dead battery. The fix is not a part replacement, but a software update for the Telematics Communication Interface Control Module (K73). A dealer can perform this recalibration.
TSB 23-NA-065: OnStar Inoperative After Importing Vehicle
This bulletin applies to 2016-2023 Chevrolet Express and GMC Savana vans. It addresses a problem where vehicles originally from Canada may not be able to connect to the U.S. cellular network, making OnStar inoperative. The fix is a software update for the Telematics control module performed by a dealer.
Buying a Used OnStar Module: The Programming Trap
This is the most critical section for anyone considering a used part. While a used OEM module is physically identical and much cheaper, it presents a major installation challenge.
Warning: A used OnStar module is 'married' to the original vehicle's Vehicle Identification Number (VIN). It cannot be installed and programmed in a different vehicle using standard dealer tools.
When a new module is installed, a GM dealer uses the Service Programming System (SPS2) to write your vehicle's VIN into it. However, this software is designed to prevent writing a VIN to a module that already has one. If a dealer tries to program a used module, the system will see the VIN mismatch and the process will fail. You will be left with a part that does not work, and the dealer will tell you that you need to buy a new module.
How to Use a Salvaged Module Successfully
While a dealer cannot do it, there are independent specialists and advanced programmers who have access to GM's engineering-level software (like GM DPS). These tools can first erase or rewrite the VIN on the used module. Once the used module is 'virginized' (cleared of its original VIN), it can then be programmed to your vehicle using the standard SPS2 software. This is not a service offered by dealerships or most independent shops. You must find a specialist who explicitly offers GM module programming for used parts.
For this reason, a used module is only a good value if you have access to one of these specialized programming services. Otherwise, you are buying a paperweight.
Replacement Overview & Module Location
Physical replacement is straightforward, but access varies by vehicle. The primary difficulty is programming, not the installation itself.
Location on 2016-2017 Acadia, Enclave & Traverse
On these SUVs, the Telematics module is located behind the glove box on the passenger side. To access it, you will need to open or completely remove the glove box assembly. This provides access to the module, which is a silver metal box held in by a few screws.
Location on 2016-2024 Express & Savana
On the Express and Savana vans, the module is typically integrated with the infotainment system behind the center dash trim and radio. Access requires carefully prying off the main dash bezel surrounding the radio and climate controls, removing the radio head unit, and then accessing the telematics module, which may be part of the radio assembly itself.
Pro Tip: Before replacing the module, first try a hard reset. On some models, simply pulling the correct fuse (often labeled OnStar, VCIM, or INFO) for 10-15 minutes and reinstalling it can resolve temporary glitches. This does not fix a hardware failure but is worth trying before spending money on a replacement.
Cost of Replacing an OnStar Module
| Part or Service | Estimated Cost |
|---|---|
| New OEM Module | $200 - $350 |
| Used OEM Module | $40 - $100 |
| New Aftermarket / Remanufactured | Not commonly available |
| Shop Labor (Installation) | $100 - $200 |
| Dealer Programming (for a new module) | $125 - $250 |
| Total Dealer Replacement (New Part) | $425 - $800+ |
Frequently Asked Questions (FAQ)
Does this module absolutely need to be programmed?
Yes, 100%. The module will not function without being programmed to your vehicle's specific VIN and options using GM's proprietary software. This is not a plug-and-play part.
Can a locksmith or independent shop program it?
An independent shop that subscribes to GM's Techline Connect software and has a J2534 passthrough device can program a new module. However, most shops and locksmiths cannot program a used module because they lack the specialized tools to change the stored VIN.
What's the difference between the 2017 GMC Acadia and the 2017 GMC Acadia Limited?
This is a major point of confusion. The 2017 GMC Acadia is a completely redesigned, smaller midsize SUV. The 2017 GMC Acadia 'Limited' is the previous, larger, first-generation body style that was continued for one more year, primarily for fleet sales. This part fits the 2017 Acadia Limited only, not the redesigned 2017 Acadia.
🎬 Watch: Troubleshooting a 2016 GMC Acadia stuck in demo mode.Can I just unplug the OnStar module to fix my battery drain?
Yes, you can unplug the module or pull its fuse to stop a parasitic draw as a temporary fix. However, this will disable all OnStar functions, potentially your in-dash navigation, and may cause a 'Service OnStar' message to remain on your dash. 🎬 See this guide on how to completely remove the module. On some vehicles where the module is part of the communication network 'daisy chain,' unplugging it can cause other modules to stop communicating.
Helpful Videos
Technical Specifications
OEM Part Numbers: 23365735 84019741 84052340 84155503 87843803
Official Name: Telematics Communication Interface Control Module (K73). Controls OnStar, 4G LTE Wi-Fi, GPS, and mobile app communication.
We Have This Part in Stock
The information in this article is provided for general reference and educational purposes only. Vehicle specifications, procedures, and part compatibility can vary by production date, trim level, and region. Always consult your vehicle's factory service manual and verify part numbers before purchasing or performing repairs. Safety-critical components such as airbags, seat belts, and braking systems should be installed by a qualified professional.
- GMC Acadia:
- Buick Enclave:
- Chevrolet Traverse:
- Chevrolet Express 2500:
- GMC Savana 2500:
- Chevrolet Express 3500:
- GMC Savana 3500:
- 🎬 Helpful Videos
- 🛍️ Shop This Part
- Symptoms of a Failing OnStar Module
- 1. Parasitic Battery Drain (The Most Common Symptom)
- 2. 'Service OnStar' Message or Red OnStar Light
- 3. Loss of OnStar Functions and App Connectivity
- 4. Associated OBD-II Trouble Codes
- Known Issues, TSBs, and Recalls
- TSB 16-NA-227: Dead Battery After Exiting with Bluetooth Active
- TSB 23-NA-065: OnStar Inoperative After Importing Vehicle
- Buying a Used OnStar Module: The Programming Trap
- How to Use a Salvaged Module Successfully
- Replacement Overview & Module Location
- Location on 2016-2017 Acadia, Enclave & Traverse
- Location on 2016-2024 Express & Savana
- Cost of Replacing an OnStar Module
- Frequently Asked Questions (FAQ)
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