U0198 on 2013-2019 Ford Fusion: Lost Communication With TCU Fixes

What's Unique About the 2013-2019 Ford FUSION

The second-generation Ford Fusion was a key part of Ford's push into connected-car technology. A major cause for U0198 on 2013-2016 models is the nationwide shutdown of 3G cellular networks (completed in Feb 2022), which rendered the original 3G TCUs obsolete. This is not a simple software glitch, but a hardware limitation requiring an upgrade to a 4G TCU. Ford acknowledged this by creating Customer Satisfaction Program 21B09 to assist owners with the upgrade. For later models with 4G TCUs, the issue is more frequently caused by software glitches between the car's TCU and Ford's servers, which is why Ford released multiple Technical Service Bulletins (TSBs) recommending a module reset or a dealer-installed software update as the primary fixes.

Diagnostic Flowchart

Tap your situation to follow the diagnostic path that matches what you're seeing on this vehicle.

Generation note: The 2013-2019 Ford Fusion covers the entire second generation (codename CD4). This issue is common across this generation, which uses the SYNC infotainment system with an integrated Telematics Control Unit. Models from 2013-2016 are particularly susceptible due to the 3G network sunset.

Symptoms You May Notice

• Remote features via FordPass or MyFord Mobile app do not work (e.g., remote start, lock/unlock)
• Inability to authorize a user for remote access, with the app showing an error.
• Modem Electronic Serial Number (ESN) is missing or blank in the SYNC/APIM settings screen.
• A 'Telematics System Fault' or 'Communication Error' message may appear on the infotainment screen.
• A parasitic battery draw can occur, leading to a dead battery if the car sits for a few days. This happens when the TCU gets stuck in a loop trying to connect to the decommissioned 3G network.

Most Likely Causes

1. Obsolete 3G TCU (Mainly 2013-2016 Models) Very High Probability These models were equipped with 3G modems. Cellular carriers, including Ford's partner AT&T, shut down their 3G networks in 2022, making it impossible for these modules to connect.
   How to confirm: The vehicle is a 2013-2016 model year and FordPass stopped working around 2022. A Ford dealer can confirm the vehicle is part of Customer Satisfaction Program 21B09 for the 3G modem.
   Typical fix: Upgrade the 3G TCU to a 4G TCU. This can be done at a dealer or as a DIY project by purchasing a 4G modem and programming it with software like FORScan.
   Est. part cost: $150-$300 (Used 4G TCU), $400+ (New 4G TCU Kit)
2. TCU Requires a Power-Cycle Reset 🔴 High Probability This is the official first step recommended by Ford in multiple Technical Service Bulletins (TSBs) to resolve temporary software glitches. [SSM 48260, SSM 46534]
   How to confirm: The code disappears and remote functions are restored after performing the reset.
   Typical fix: Locate the fuse for the TCU, remove it for at least 5 minutes, and then reinstall it. This forces the module to reboot. 🎬 Watch this quick 10-minute fix for FordPass connectivity issues. The fuse is often F79 (5A) in the passenger compartment fuse box (under the dash to the left of the steering wheel). 🎬 See exactly where to find the TCU fuse in your Fusion.
   Est. part cost: $0
3. Outdated TCU or Gateway Module (GWM) Software 🟡 Medium Probability Ford frequently released software updates to fix communication bugs between the vehicle and its servers. TSBs repeatedly advise dealers to check for and perform any open Field Service Actions (FSAs). [SSM 47471, SSM 47198, SSM 47161]
   How to confirm: A Ford dealer or a shop with a Ford-specific scan tool (like FDRS) can check for available software updates for the TCU or GWM.
   Typical fix: Reprogramming the module with the latest software calibration. This must be done by a dealer or a qualified independent shop.
   Est. part cost: $0 (parts), $120-$250 (labor for programming).
4. Faulty Telematics Control Unit (TCU) ⚪ Low Probability While less common than software or obsolescence issues, the internal hardware of the 4G module can fail, preventing it from communicating on the vehicle's network.
   How to confirm: The U0198 code persists after a successful fuse pull and after a dealer has confirmed no software updates are available or that updates fail to install.
   Typical fix: Replacement of the TCU module. The new module will require programming by a dealer or with FORScan to link it to the vehicle's VIN.
   Est. part cost: $150-$300 (used), $400-$600 (new)

Rare But Worth Checking

• Wiring or Connector Issue: Although less common for this specific code, damage to the CAN bus wiring harness or corrosion in the TCU's connector can interrupt communication. A visual inspection is worthwhile if other fixes fail.
• Low Battery Voltage: Control modules can behave erratically when system voltage is low. Before diagnosing complex network issues, ensure the battery is fully charged and in good health. A failing TCU can also cause a parasitic draw that drains the battery.

Diagnosis Steps

1. Check for open recalls or Customer Satisfaction Programs (like 21B09 for the 3G modem) for your vehicle's VIN on the official Ford website.
2. Attempt to reset the TCU. Locate the fuse for the 'TCU', 'Telematics', or 'Modem'. For many Fusions, this is fuse F79 (a 5A fuse) in the passenger compartment fuse box, located under the dashboard to the left of the steering column. Your owner's manual will have the definitive location.
3. Remove the correct fuse and wait for a full 5 minutes before reinstalling it. [SSM 48260]
4. Clear the trouble codes using an OBD-II scanner and start the vehicle. Check if remote features work and if the code returns.
5. If the code persists, check the battery to ensure it has a healthy state of charge (above 12.4 volts). A parasitic draw from the TCU may have weakened it.
6. If the battery is good and the reset failed, the next step is to visit a Ford dealer or a qualified repair shop to check for and install any available software updates for the TCU or GWM.
7. If the vehicle is pre-2017 and software updates do not work, the 3G TCU is obsolete and must be upgraded to a 4G unit.
8. If all other steps fail on a 4G-equipped vehicle, the TCU module itself is the likely culprit and requires replacement and programming.

Parts You'll Likely Need

• 4G Telematics Control Unit (TCU) (OEM #KS7T-14G229-AH, JL3T-14G229-AJ, HJ5T-14G087-UF) — This is the module that fails or becomes obsolete (3G models). Upgrading to a 4G version is the permanent fix for older vehicles. Part numbers starting with H, J, K, or L are typically 4G.
  Trusted brands: Motorcraft (OEM), Visteon (OEM supplier), Continental (OEM supplier)
  OEM price range: $400-$600
  Aftermarket price range: $150-$300 (Used/Remanufactured)

Related Codes That Often Appear With This One

• U0140 - Lost Communication With Body Control Module (BCM)

Technical Service Bulletins (TSBs) & Recalls

• SSM 48260: Notes inoperative remote features and recommends removing the TCU fuse for 5 minutes.
• SSM 47471: Mentions inoperative FordPass features and recommends performing open TCU field service actions (FSAs).
• SSM 46534: Cites a discharged battery and inoperative remote features, recommending FSAs and a TCU fuse pull.
• SSM 47198: Similar to others, points to FSAs as the primary corrective action for the U0198 DTC.
• SSM 47161: Recommends performing FSAs and, if the code remains, pulling the TCU fuse before reprogramming the module.
• TSB 22-2230 / 22-2309: Addresses issues where a vehicle cannot be authorized in the FordPass app after a 3G to 4G modem upgrade, often requiring a Valet Mode toggle or PMI process.

Platform-Specific Known Issues

• 3G Network Sunset: The single biggest issue for 2013-2016 models. The original 3G modems are obsolete. Ford's Customer Satisfaction Program 21B09 covered the labor for a customer-paid 4G upgrade kit, but this program expired in July 2023.
• Parasitic Battery Drain: A known side effect where the TCU, unable to find a cellular signal, remains active and drains the 12V battery. This is cited in TSB SSM 46534 and widely discussed by owners.
• DIY Upgrade Path: A strong community of owners has documented the process of upgrading the TCU from 3G to 4G using the FORScan software, which allows for programming the new module without a dealer visit.

Mechanic-Grade Diagnostic Values

• HS-CAN Bus Voltage (Normal Operation) — expected: Two signals that mirror each other, with CAN-H typically swinging between 2.5V and 3.5V, and CAN-L swinging between 2.5V and 1.5V. The sum of the two voltages should be ~5V. A lab scope will show clean, square waves.. Failure: No signal, a flat line, or a noisy/distorted signal on one or both CAN lines. A short to ground will pull the voltage low; a short to power will pull it high.
• TCU Power Supply Voltage — expected: Stable 12V+ (typically ~12.4V with engine off, ~14V with engine running) at the TCU's power pin/fuse.. Failure: Voltage below 12V, or no voltage, indicates a problem with the power supply circuit or a blown fuse.
• TCU Ground Connection Resistance — expected: Less than 0.2 Ω between the TCU's ground pin and a clean chassis ground point.. Failure: A reading above 0.2 Ω indicates a poor ground connection due to corrosion or a loose fastener, which can cause intermittent communication issues.

Hidden / Shadow Codes Worth Checking

• U2402:00 - Control Module Programming/Configuration Incompatible: This code in the Gateway Module (GWM) indicates a mismatch between the expected and actual configuration of a module on the network, such as the TCU. (see via Ford's official diagnostic software (IDS/FDRS). Often set when a TCU is missing or has failed.)
• U2402:92 - Control Module Programming/Configuration Incompatible: Performance or Incorrect Operation: A variant of the above, also stored in the GWM, pointing to an operational or performance issue with a module's configuration, which can be triggered by a faulty TCU. (see via Ford's official diagnostic software (IDS/FDRS).)

Scan Tool Commands That Help

• Ford FDRS/IDS: Programmable Module Installation (PMI) — This function is required after physically installing a new or used TCU. It downloads the vehicle-specific configuration from the old module (if possible) or from Ford's servers and writes it to the new module, linking it to the car's VIN.
• Ford FDRS/IDS: Network Test — This is a primary diagnostic step. The tool attempts to communicate with every module on the network. A 'TCU not responding' result during this test confirms the communication loss that sets code U0198.
• FORScan: Module Configuration (As-Built Format) — Used in the DIY community to manually program a replacement TCU. Technicians load a known-good 'As-Built' data file for their vehicle type into the new module to enable its features, bypassing the need for a dealer's online connection.

Wiring & Ground Locations

• Telematics Control Unit (TCU) — Located behind the passenger side glovebox. Requires removal of the glovebox assembly to access.. This is the physical location of the module. Access is needed to check connectors for corrosion, test for power/ground at the module, or to replace it.
• G200 — A primary dashboard ground point located at the left center of the dash, near the steering column area.. A poor connection at this shared ground point can cause communication issues for multiple modules in the dashboard area, including the APIM or other related components.
• G100 / G102 — Ground points located in the left front of the engine compartment.. While less likely to be the primary cause for an interior module, checking major engine bay grounds is a good practice as they are part of the overall vehicle grounding scheme that all modules rely on.

Real Owner Repair Stories

• Reddit user on r/Ford (2019 Ford Edge Titanium (platform-mate with similar technology)) — FordPass app stopped working, dealer diagnosed U0198.
  ❌ Tried (didn't work) Dealer diagnosis which recommended a $1,200 TCU replacement.
  ✅ What actually fixed it The owner, after finding information online, located the fuse for the TCU, pulled it for 5 minutes, and reinstalled it. This power-cycled the module and fully restored its function, resolving the code and the app connectivity issue for $0.
• Ford Focus Electric Forum user (2015 Ford Focus Electric (shares 3G TCU obsolescence issue)) — U0198 code in both APIM and PCM, 12V battery draining overnight, and the 12V battery was not charging correctly while driving.
  ❌ Tried (didn't work) Replacing the 12V battery did not solve the drain.
  ✅ What actually fixed it The immediate fix to stop the battery drain was pulling the fuse for the TCU (Fuse F1 in the trunk on that model). The permanent fix discussed is upgrading the obsolete 3G TCU to a 4G unit to restore functionality and eliminate the source of the parasitic draw.

OEM Part Supersession History

• G-series (e.g., GJ5T-14G229-BM) → H, J, K, and L series (e.g., HJ5T-14G087-UF, KS7T-14G229-AH) — Hardware upgrade from 3G cellular technology to 4G LTE. The 3G network was shut down, rendering the older modules obsolete.
  Heads up: A 3G TCU will not work on modern cellular networks. A 4G TCU must be programmed to the vehicle using FDRS or FORScan; it is not plug-and-play. Some specific vehicle models (like Energi hybrids) may require a specific series of 4G modem (e.g., HJ5T) for full feature compatibility.

Model Year Variations Within This Range

• 2013-2016: These models were originally equipped with 3G TCUs and the MyFord Touch infotainment system. The primary cause of U0198 is the obsolete 3G hardware.
• 2017-2019: These models received a facelift and the newer SYNC 3 infotainment system. They were equipped with 4G TCUs from the factory. For these vehicles, U0198 is almost always caused by a software glitch requiring a fuse pull reset, a dealer software update (PMI), or a rare hardware failure of the 4G module itself.