2020-2021 Expedition & Navigator Gateway Module: Decoding Failures and Programming

Symptoms of a Failing Serial Data Gateway Module

Because the Gateway Module is central to all vehicle communications, a failure can cause a wide and confusing array of problems. The symptoms are often intermittent and can seem completely unrelated to each other. One of the most common indicators of a GWM issue is when a diagnostic scan tool cannot communicate with multiple modules or reports widespread communication fault codes.

• Multiple Warning Lights: The dashboard may light up with numerous warnings simultaneously, such as 'Antilock Brake Fault,' 'Restraints Indicator Warning,' and 'Hill Start Assist Warning'.
• Loss of Features: Non-essential systems may stop working intermittently or all at once. This can include the SYNC infotainment screen going blank, the climate control shutting down, or power-retractable running boards failing to deploy.
• Drivability Problems: In more severe cases, a GWM failure can affect critical systems. You might experience a sudden loss of power as the vehicle enters a reduced-power 'limp mode,' or face an intermittent no-start or crank-no-start condition.
• Network Communication Errors: A message like "Vehicle Network Communication Error" may appear on the center display.
• Battery Drain: A faulty Gateway Module can fail to go to 'sleep' when the vehicle is off, causing it to continue drawing power and draining the battery.

Known Issues, Recalls, and Technical Service Bulletins (TSBs)

While no direct recalls exist for widespread failure of the Gateway Module itself on the 2020-2021 Expedition and Navigator, several related service campaigns and known issues highlight the complexity of the vehicle's electrical system.

Customer Satisfaction Program 22N15

On some Ford models, the Gateway Module software prevented proper communication with state emissions testing equipment, leading to a failed inspection. This was not a part failure, but a software issue. Ford initiated a program to reprogram the GWM software to correct this. If you are failing an emissions test due to a 'not ready' status or communication error, check with a dealer to see if your vehicle is eligible for this or a similar software update.

Recall 20S20: Pre-Collision Assist Inoperative

Some 2020 Expedition and Navigator models were recalled because the Pre-Collision Assist feature was not enabled due to incorrect software coding in various modules. The fix required a dealer to reprogram the Body Control Module (BCM), ABS module, Instrument Panel Cluster (IPC), and others. This shows how a software issue, not a hardware failure, can disable a key feature and require a complex reprogramming procedure.

Recall for Battery Junction Box Fire Risk (22S36 / 22S48)

A recall was issued for certain 2020-2021 Expedition and Navigator models due to a manufacturing defect in the underhood Battery Junction Box (BJB), which could cause an electrical short and potential fire, even with the vehicle off. While not a GWM issue, a faulty BJB can cause a host of strange electrical symptoms that could be mistaken for a module failure.

Intermittent Electrical 'Ghosts'

Owners have reported difficult-to-diagnose electrical issues, such as the liftgate opening on its own or intermittent no-starts, that have stumped even dealerships. In some cases, these problems are traced to other modules on the network, like the Remote Function Actuator (RFA), creating 'noise' that disrupts communication and mimics a GWM failure. In another instance, a poorly installed third-party GPS tracker damaged the GWM connector, causing random electrical faults when going over bumps. This highlights the importance of checking for any aftermarket devices connected near the OBD-II port before condemning the Gateway Module.

Buying a Used Serial Data Gateway Module

A used OEM Gateway Module is a cost-effective alternative to a new part, but you must be careful to ensure compatibility and factor in the mandatory programming costs. This is THE most important section for anyone considering a used GWM.

1. Match the Part Number Exactly

The single most critical step is to match the OEM part number on your original module to the one you are purchasing. For the 2020-2021 Expedition and Navigator, the primary part numbers are LL1T-14F642-AC and LL1Z-14F642-A. Do not rely on visual appearance alone. A module from a different model year or vehicle may look identical but have different internal hardware or firmware, making it incompatible.

2. Physical Inspection

When you receive the used module, inspect it for:

• Connector Pins: Check the pins in the electrical connectors for any signs of corrosion, bending, or damage. A damaged pin can cause a poor connection and persistent issues.
• Signs of Water Damage: Look for any chalky residue or discoloration on the casing, which could indicate past exposure to moisture. Never install a part from a flood-damaged vehicle.
• Aftermarket Tampering: Be wary of any signs that the module's casing has been opened or that aftermarket devices have been spliced into its wiring harness.

3. Budget for Programming

A used module is an un-programmed blank slate. It will not work correctly until it is programmed to your vehicle. You MUST have a plan for programming before you buy the part. This service is typically performed by:

• A Ford or Lincoln dealership service center.
• An independent auto repair shop that subscribes to and is proficient with Ford's Diagnostic and Repair System (FDRS).

Call ahead to get a quote for programming a customer-supplied used module. Some shops may have policies against installing customer-supplied parts, so confirm this beforehand. Expect to pay for 1-2 hours of labor for the diagnosis and programming service.

Cost Comparison for a Serial Data Gateway Module

The cost of replacing the GWM involves the part itself and the labor for installation and programming. The physical swap is quick, but programming is where the cost lies.

Frequently Asked Questions (FAQ)