WOMS
U code network Medium severity

U1149 SCP (J1850) Invalid or Missing Data for Audio Control

The OBD2 code U1149 SCP (J1850) Invalid or Missing Data for Audio Control indicates that the vehicle's audio control module is not receiving valid data or is unable to communicate properly with other modules in the...

Definition

The OBD2 code U1149 SCP (J1850) Invalid or Missing Data for Audio Control indicates that the vehicle's audio control module is not receiving valid data or is unable to communicate properly with other modules in the network

Common causes

  • Faulty audio control module
  • Poor or damaged wiring/connectors
  • Corrupted software in the audio control module
  • Communication issues between modules
  • Low battery voltage or power supply issues
  • Faulty or malfunctioning J1850 communication bus
  • Interference from aftermarket audio equipment
  • Grounding issues in the audio system

Common misdiagnoses

  • Faulty audio control module
  • Wiring issues or shorts in the audio system
  • Faulty or corroded connectors
  • Issues with the vehicle's battery or charging system
  • Problems with the vehicle's data bus or communication network
  • Incorrectly programmed or incompatible audio system components
  • Faulty ground connections related to the audio system

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 the Wiring and Connectors

    Visual Inspection: Check the wiring and connectors related to the audio control system for any signs of damage, corrosion, or loose connections

  3. 3. Connector Pins

    Ensure that the pins in the connectors are not bent or corroded

  4. 4. Test the Audio Control Module

    If accessible, test the audio control module for proper operation. This may involve checking for power and ground at the module

  5. 5. If possible, perform a functional test of the audio system to see if it operates correctly

  6. 6. Check the SCP (J1850) Communication

    Use a scan tool to monitor the SCP (J1850) communication bus. Look for any irregularities in the data being transmitted

  7. 7. Check for any shorts or opens in the communication lines

  8. 8. Inspect Related Components

    Check other components that may be related to the audio system, such as the radio, speakers, and any amplifiers. Ensure they are functioning correctly

  9. 9. Battery and Ground Connections

    Ensure that the vehicle’s battery is in good condition and that all ground connections are secure. Poor grounding can lead to communication issues

  10. 10. Software Updates

    Check if there are any software updates available for the vehicle’s audio control module or the vehicle’s main computer. Sometimes, manufacturers release updates to fix known issues

  11. 11. Clear Codes and Test Drive

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

  12. 12. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued bulletins regarding known issues with the audio control system

  13. 13. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or an automotive technician who has experience with the specific vehicle and its systems. By following these steps, you should be able to identify the root cause of the U1149 code and take appropriate action to resolve the issue