WOMS
U code network Medium severity

U0549 Invalid Data Received From Remote Accessory Module

The OBD2 code U0549 indicates that the vehicle's control module has received invalid or corrupted data from a remote accessory module, which may affect the operation of certain vehicle functions

Definition

The OBD2 code U0549 indicates that the vehicle's control module has received invalid or corrupted data from a remote accessory module, which may affect the operation of certain vehicle functions

Common causes

  • Faulty Remote Accessory Module (RAM)
  • Wiring issues or damaged connectors
  • Corrupted software or firmware in the RAM
  • Communication network issues (CAN bus problems)
  • Power supply issues to the RAM
  • Grounding problems
  • Interference from other electronic devices
  • Faulty vehicle control modules

Common misdiagnoses

  • Faulty Remote Accessory Module
  • Wiring issues or short circuits
  • Faulty Body Control Module (BCM)
  • Communication network problems (CAN bus issues)
  • Battery or power supply issues
  • Software or firmware glitches
  • Faulty sensors related to the accessory module
  • Incorrectly configured aftermarket accessories

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Sometimes, multiple codes can provide more context for the issue

  2. 2. Inspect Wiring and Connectors

    Examine the wiring and connectors related to the Remote Accessory Module. Look for signs of damage, corrosion, loose connections, or frayed wires. Repair or replace any damaged components

  3. 3. Check the Remote Accessory Module

    If the wiring and connectors are in good condition, the issue may lie with the Remote Accessory Module itself. Inspect the module for any visible damage or signs of failure

  4. 4. Test the Module

    If possible, test the Remote Accessory Module using a multimeter or diagnostic tool to ensure it is functioning correctly. Some vehicles may allow you to perform a module self-test

  5. 5. Check for Software Updates

    Sometimes, the issue can be resolved with a software update. Check with the vehicle manufacturer or a dealership to see if there are any updates available for the vehicle's control modules

  6. 6. Inspect Related Components

    The RAM may interact with other components (like the Body Control Module or other accessory modules). Check these components for faults or communication issues

  7. 7. Clear Codes and Test Drive

    After performing any repairs or inspections, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns

  8. 8. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the U0549 code for your specific vehicle make and model. Manufacturers may have issued guidance on common issues and fixes

  9. 9. Professional Diagnosis

    If the issue persists after performing the above steps, it may be necessary to seek help from a professional mechanic or dealership with advanced diagnostic tools. By following these steps, you can systematically identify and address the root cause of the U0549 code