U0197: How to Diagnose & Fix — Lost Communication With Telephone Control Module
2 vehicles · 2 makes
How to diagnose and fix U0197: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Volvo XC90 · 2023–2025
Owners of SPA-platform Volvos including the 2023-2025 XC90 continue to report TCAM-related failures where the vehicle loses cellular service, Volvo Cars app communication, GPS position, remote start/lock functions, and sometimes emergency-call features. In many cases the issue appears as an intermittent 'SOS service required' or connectivity warning, often after software glitches or low-voltage events. The problem is well documented in owner forums and dealer service visits, with some vehicles requiring module reset, software reload, or TCAM replacement.
Common Symptoms
- SOS service required message
- No LTE or internet connection
- Volvo Cars app cannot communicate with vehicle
- Remote lock/unlock or remote start unavailable
- GPS location incorrect or unavailable
- Intermittent eCall/telematics warnings
How to Fix
Diagnose battery state and low-voltage history first, then scan the telematics network and verify antenna/module communication. Dealers often perform a TCAM reset, software reload, or replace the TCAM if faults return. If the vehicle also has repeated 12V battery warnings, address battery condition and charging-system behavior because undervoltage can trigger or worsen telematics faults.
Sources for this issue (1)
Chevrolet Equinox · 2024–2026
The telematics control module — the OnStar unit — fails on a large scale across the redesigned Equinox and the Equinox EV. It is the single largest complaint cluster in NHTSA's electrical-system category for the 2025 Equinox. When the module fails it stops sleeping and continuously draws current, flattening the 12-volt battery; owners report waking to a dead vehicle and, in the worst cases, the car shutting down mid-drive, with one report of the battery measured at 0.03 volts. The failure simultaneously disables every OnStar-dependent safety and convenience function: Automatic Crash Response, emergency calling, GPS position (which can read miles off), remote start, remote lock/unlock through the myChevrolet app, and over-the-air update delivery. Replacement modules have been on nationwide backorder for extended periods, with owners reporting month-plus waits and at least one case where the replacement module was itself faulty. GM has not issued a recall or a public service bulletin for the defect.
Common Symptoms
- Dead 12V battery repeatedly, especially after the car sits a day or two
- Vehicle shuts down or loses power while driving
- OnStar unavailable / 'Service OnStar' message
- Remote start and remote lock/unlock stop working in the myChevrolet app
- GPS location wrong by miles
- Automatic Crash Response and emergency calling inoperative
- Dealer says the telematics module is on national backorder
How to Fix
Have the dealer perform a parasitic draw test with the telematics module fused out to confirm the module is the current draw before replacing the 12-volt battery — repeatedly replacing a battery that a failed TCM is killing wastes money and does not fix the fault. Confirm the diagnosis by checking whether OnStar services, app remote commands and GPS position are all dead at once, which points at the module rather than the battery. Open a case with GM Customer Assistance to get a parts-priority escalation and a loaner while the module is on backorder, and keep every repair order — the combination of a documented safety-system loss and a long parts wait is the basis for a state lemon-law or Magnuson-Moss claim. As a stopgap, a battery tender will keep the vehicle startable but does not restore crash response.
Sources for this issue (3)
Find U0197 by make
Browse every documented model and issue for your make.
U0197 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does U0197 mean?
U0197 stands for "Lost Communication With Telephone Control Module." A generic network code that sets when a module loses the expected data messages from the Telephone Control Module, which manages hands-free/Bluetooth phone functions. Set after the module fails to respond for a calibrated period.
What are the most common causes of U0197?
The most common causes of U0197 are: Loss of power or ground to the telephone control module, Open, shorted, or corroded bus wiring, Loose or corroded connector, Blown fuse, Failed telephone control module. The specific cause varies by vehicle.
How much does it cost to fix U0197?
Repair costs vary widely depending on the root cause and vehicle.
Which vehicles are affected by U0197?
Au7o has documented U0197 across 2 vehicle models from 2 manufacturers: Chevrolet, Volvo.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.