Experiencing issues with your 2011 Lincoln MKX key fob? It’s a common frustration when your key fob suddenly stops working, leaving you unable to start your vehicle or access its features. The immobilization effect you’re encountering is likely due to the Passive Anti-Theft System (PATS), a sophisticated security system in your Lincoln MKX. This system relies on the interaction between your Intelligent Access (IA) key fob, the start button, and several electronic modules within your vehicle.
To understand why your 2011 Lincoln MKX key fob might not be working, and potentially troubleshoot the issue, let’s delve into the workings of the PATS with Intelligent Access system, drawing information directly from the 2011 Edge Workshop Manual, which shares similar systems with the MKX.
Decoding the Passive Anti-Theft System (PATS) in Your 2011 Lincoln MKX
The PATS system is designed to prevent vehicle theft by immobilizing the engine if an unauthorized key is used. In your 2011 Lincoln MKX equipped with Intelligent Access, this system comprises several key components working in concert:
- Intelligent Access (IA) key fob: This is your primary interface with the vehicle’s security system.
- Front passive start antenna: Located at the bottom front of the floor console, it helps detect the key fob’s presence inside the vehicle.
- Center passive start antenna: Situated in the rear of the floor console, it expands the key fob detection area within the cabin.
- Rear passive start antenna: Positioned under the liftgate scuff trim panel, it allows for key fob detection near the rear of the vehicle.
- Backup transceiver: Found in the floor console beneath the audio jacks, it acts as a secondary communication point for the key fob.
- Tire Pressure Monitor (TPM) module: While primarily for tire pressure monitoring, it interacts with the vehicle’s communication network.
- Remote Function Actuator (RFA) module: Located behind the glove compartment, this module is central to the PATS and Intelligent Access functionality.
- Body Control Module (BCM): The BCM manages various body electronics and communicates with other modules, including the RFA.
- Powertrain Control Module (PCM): The PCM controls the engine and is crucial for the PATS immobilization and engine starting process.
Image: Location of the backup transceiver within the floor console of a 2011 Lincoln MKX, a key component of the PATS system.
Starting System Operation with Intelligent Access: What Happens When You Press Start?
When you attempt to start your 2011 Lincoln MKX using the start/stop button, a sequence of electronic verifications occurs to ensure it’s a legitimate start attempt. Here’s a simplified breakdown:
NOTE: The PATS system, managed by the Remote Function Actuator (RFA) module, will prevent the engine from starting if an unprogrammed key is used or an invalid PCM ID is detected. If a PATS issue prevents starting, the Instrument Panel Cluster (IPC) will display a “STARTING SYSTEM FAULT” message.
The Intelligent Access starting system is governed electronically by the RFA module, which serves as the PATS control center. The RFA module requires several inputs to authorize a start:
- Brake pedal applied input: Ensures the vehicle is in a safe starting condition.
- Start/stop switch is pressed: Initiates the starting sequence.
- Transmission in PARK or NEUTRAL signal: Confirms the transmission is in a safe starting gear.
- Run/start relay voltage: Verifies power to the starting system.
- Correctly coded ignition key signal from the RFA: This is the critical PATS verification step.
During the start process:
- Pressing the start/stop button and brake pedal sends a start request to the RFA module and BCM.
- The RFA module communicates with the BCM to initiate the engine start sequence.
- The BCM, after receiving the command from the RFA, communicates with the PCM.
- The BCM initializes and verifies module IDs: It checks the IDs of the RFA module and PCM against the IDs stored in its memory.
- PATS Enabled (if IDs match): If the RFA and PCM IDs match the stored IDs in the BCM, the PATS system is enabled, and the starting process can proceed.
- The PCM, recognizing valid inputs and PATS authorization, energizes the starter relay coil.
- The starter relay contacts close, providing power to the starter solenoid, and the starter motor cranks the engine.
- The PCM disengages the starter motor once the engine reaches a certain RPM, a set cranking time is exceeded, or the stop/start button is pressed to shut down the engine.
Image: The Remote Function Actuator (RFA) module’s location behind the glove compartment in a 2011 Lincoln MKX. This module is crucial for key fob and PATS operation.
Understanding the Remote Function Actuator (RFA) Module
The Remote Function Actuator (RFA) module is exclusive to vehicles with the Intelligent Access feature, like your 2011 Lincoln MKX. It plays a central role in managing Intelligent Access, entry/anti-theft systems, and communicates via the Medium Speed Controller Area Network (MS-CAN). The RFA module’s functions include:
- Intelligent Access (IA) feature control
- Keyless entry keypad illumination
- Liftgate release operation
- Passive Anti-Theft System (PATS) management
- Power door locks control
- Remote Keyless Entry (RKE) system functionality
Diagnostic Resources for Your 2011 Lincoln MKX Key Fob Issues
If you’re facing a “2011 Lincoln Mkx Key Fob Not Working” situation, diagnosing the root cause can be complex. The following documents, extracted from the 2011 Edge Workshop Manual, provide detailed information on component interactions, wiring diagrams, electrical connector details, and diagnostic procedures. These resources can be invaluable whether you plan to troubleshoot yourself or want to be better informed before consulting a service technician.
Document Download Links:
Anti-Theft — With Intelligent Access (IA) – Diagnosis and Testing
Starting System – Diagnosis and Testing
Remote Function Actuator (RFA) Module – Diagnosis and Testing
Handles, Locks, Latches and Entry Systems — With Intelligent Access (IA) – Diagnosis and Testing
Tire Pressure Monitoring System (TPMS) – Diagnosis and Testing
Body Control Module (BCM) – Removal and Installation
Body Control Module (BCM) Fuse Protected-Circuits Legend – HIGHLIGHTED – Wiring Diagram
Remote Function Actuator (RFA) Module – Removal and Installation
Remote Function Actuator (RFA) Module – Enhanced Image
Powertrain Control Module (PCM) – Removal and Installation
Tire Pressure Monitor (TPM) Module – Removal and Installation
Passive Anti-Theft System – Wiring Diagram – Cell 112 , Page 02
Passive Anti-Theft System – Wiring Diagram – Cell 112 , Page 03
Power Distribution-BCM – Wiring Diagram – Cell 013, Page 12
Remote Keyless Entry and Alarm – Wiring Diagram – Cell 117, Page 06
Remote Keyless Entry and Alarm – Wiring Diagram – Cell 117, Page 07
Remote Keyless Entry and Alarm – Wiring Diagram – Cell 117, Page 08
Remote Keyless Entry and Alarm – Wiring Diagram – Cell 117, Page 09
Remote Keyless Entry and Alarm – Wiring Diagram – Cell 117, Page 10
Starting System -Wiring Diagram – Cell 020, Page 02
Tire Pressure Monitor System – Wiring Diagram – Cell 118, Page 01
Backup Transceiver – Connector C3371 Location (Floor Console)
Remote Function Actuator (RFA) Module – Connector C2153A Details
Remote Function Actuator (RFA) Module – Connector C2153B Details
Remote Function Actuator (RFA) Module – Connector C2153C Details
Remote Function Actuator (RFA) Module – Connector C2153D Details
Remote Function Actuator (RFA) Module – Connector C2153E Details
Remote Function Actuator (RFA) Module – Connectors Location (Behind Glovebox)
To effectively diagnose your 2011 Lincoln MKX key fob issue, it’s recommended to start by scanning your vehicle for Diagnostic Trouble Codes (DTCs). These codes can provide valuable clues and pinpoint which system or component is malfunctioning. The linked diagnosis and testing documents will be particularly useful in interpreting DTCs and guiding you to the appropriate pinpoint tests.
Remember to consult a qualified automotive technician if you are not comfortable performing electrical diagnostics or repairs yourself.
Good luck!
