Lincoln Navigator modem TCU failure after oil change requiring replacement on Lincoln Navigator

Some Lincoln Navigator owners report experiencing modem or Telematics Control Unit (TCU) failures after an oil change, which can lead to issues with remote features and connectivity. These problems may arise due to the current embedded modem being unsupported, prompting the need for a modem replacement offered by Ford and Lincoln. Additionally, owners may need to upgrade from 3G to 4G, as many carriers have phased out their 3G networks. Some users find that using a diagnostic scan tool to initiate the Preventive Maintenance Inspection (PMI) process for the TCU can be helpful. In certain cases, removing the TCU fuse for 5 minutes before programming can resolve inoperative features accessed through the Ford Pass or Lincoln Way mobile app. After replacing the TCU, it may be necessary to update its firmware to ensure compatibility with the vehicle's systems. Owners are also advised to test the app functions, such as locking, unlocking, and remote starting, to confirm successful TCU replacement. For those needing replacement parts, sourcing compatible TCUs from platforms like eBay is a viable option. Following these steps can help restore functionality and connectivity in the Lincoln Navigator.