Perform a comprehensive diagnostic scan using an OBD-II scanner to retrieve stored trouble codes, freeze frame data, and system status information from the powertrain, chassis, and body control modules.

Warnings

Tools required

Preparation

1. Park vehicle on level ground and engage parking brake
2. Ensure ignition is in the OFF position
3. Verify battery voltage is at least 12.4V to prevent communication errors during scanning
4. Have vehicle information ready: VIN, current mileage, and description of any symptoms or concerns
5. Ensure all vehicle accessories are turned off (radio, climate control, lights)

Procedure

1. 1

   Locate the OBD-II diagnostic port
   The OBD-II port is located under the driver's side dashboard, to the left of the steering column near the hood release lever. Remove any protective cover if present.
2. 2

   Connect the diagnostic scanner
   Firmly plug the OBD-II scanner into the diagnostic port until it is fully seated. The connection should be snug with no gaps. Most scanners will power on automatically when the ignition is turned on.
3. 3

   Turn ignition to ON position
   Turn the ignition key to the ON/RUN position without starting the engine, or press the START button twice without pressing the brake pedal. All dashboard warning lights should illuminate briefly. Wait for the scanner to establish communication with the vehicle, which typically takes 10-30 seconds.
4. 4

   Enter vehicle information
   If prompted by the scanner, enter or confirm the vehicle VIN. The scanner should auto-detect the 2021-2024 Ford F-150 with 3.5L EcoBoost engine. Verify the displayed vehicle information matches your truck before proceeding.
5. 5

   Scan powertrain control module (PCM)
   Select the PCM or Powertrain module from the scanner menu. Retrieve all stored diagnostic trouble codes (DTCs), pending codes, and permanent codes. Record each code number and description. Note the freeze frame data for each code, which captures engine conditions when the fault occurred (RPM, load, temperature, speed, etc.).
6. 6

   Check transmission control module (TCM)
   Navigate to the TCM or Transmission module. Retrieve all stored, pending, and permanent codes. The 10-speed automatic transmission has its own dedicated control module. Record all codes and freeze frame data, paying attention to transmission temperature, gear position, and shift patterns.
7. 7

   Scan ABS and traction control systems
   Access the ABS or Brake Control Module. Retrieve all codes related to anti-lock brakes, traction control, and stability control systems. Record wheel speed sensor data and any fault codes with their freeze frame information.
8. 8

   Check body control module and other systems
   Scan the BCM (Body Control Module) and any other available modules including airbag/restraint system, HVAC, instrument cluster, and four-wheel drive system if equipped. Record all codes from each module. The F-150 may have 20+ individual modules depending on equipment level.
9. 9

   Review system readiness monitors
   Access the I/M Readiness or Emissions Monitors section. Check the status of all OBD-II monitors (Catalyst, Evaporative System, Secondary Air, Oxygen Sensors, EGR, etc.). Record which monitors show 'Ready' or 'Complete' versus 'Not Ready' or 'Incomplete'. Not Ready monitors indicate the vehicle has not completed self-tests since codes were last cleared.
10. 10

    Capture live data stream
    If diagnosing a specific symptom, record live data from relevant sensors while the engine is running or during a test drive. Key parameters for the 3.5L EcoBoost include: boost pressure, fuel pressure (both low and high pressure), oxygen sensor voltages, short and long-term fuel trims, coolant temperature, intake air temperature, MAF sensor readings, and throttle position.
11. 11

    Document all findings
    Record all diagnostic information including: all DTCs from all modules with descriptions, freeze frame data, monitor status, and any relevant live data snapshots. Note the total number of codes and which systems are affected. Take photos of scanner screens if needed for reference.
12. 12

    Disconnect scanner and restore vehicle
    Turn the ignition OFF. Disconnect the OBD-II scanner from the diagnostic port. Reinstall any protective covers. Do not clear codes unless diagnostic work will be performed immediately, as this erases valuable diagnostic information and resets readiness monitors.

Reassembly

1. No disassembly is required for this procedure

Verification

• Review all recorded diagnostic codes and compare against Ford Technical Service Bulletins (TSBs) for known issues with 2021-2024 F-150 3.5L EcoBoost engines
• Verify that all control modules communicated successfully with no 'No Communication' or 'Unable to Connect' errors
• Confirm that freeze frame data was captured for all stored codes
• Check that readiness monitor status was recorded for emissions-related diagnostics
• If multiple unrelated codes are present across different modules, verify battery voltage and charging system health, as low voltage can cause false codes
• Cross-reference any turbocharger-related codes (P0234, P0299, etc.) with boost pressure data, as the twin-turbo EcoBoost system is a common source of trouble codes

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