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U code network Low severity

U1155 SCP (J1850) Invalid or Missing Data for Compact Disc

The OBD2 code U1155 indicates that there is invalid or missing data related to the Compact Disc (CD) player, specifically in the context of the SCP (J1850) communication protocol

Definition

The OBD2 code U1155 indicates that there is invalid or missing data related to the Compact Disc (CD) player, specifically in the context of the SCP (J1850) communication protocol

Common causes

  • Faulty or damaged wiring/connectors
  • Malfunctioning compact disc player
  • Poor ground connection
  • Issues with the vehicle's communication network
  • Software or firmware glitches
  • Corrupted data signals
  • Faulty control module
  • Interference from aftermarket devices

Common misdiagnoses

  • Faulty CD player
  • Wiring issues
  • Faulty audio system
  • Software glitches
  • Faulty communication module
  • Corrupted data in the vehicle's computer
  • Incorrectly installed aftermarket audio equipment

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Other codes can provide additional context for the problem

  2. 2. Inspect Wiring and Connectors

    Visually inspect the wiring and connectors related to the CD player and the SCP bus. Look for signs of damage, corrosion, or loose connections

  3. 3. Ensure that all connectors are securely plugged in and that there are no bent pins

  4. 4. Test the CD Player

    If possible, test the CD player in another vehicle to see if it functions correctly. If it does not work in another vehicle, the CD player may be faulty and need replacement

  5. 5. Check the SCP Bus

    Use a multimeter or an oscilloscope to check the SCP bus for proper voltage and signal integrity. Look for any interruptions or shorts in the communication lines

  6. 6. Ensure that the SCP bus is not being interfered with by other devices or components

  7. 7. Inspect the Vehicle's Grounding

    Ensure that the vehicle's grounding points are clean and secure. Poor grounding can lead to communication issues

  8. 8. Reset the System

    Disconnect the vehicle's battery for a few minutes to reset the system. Reconnect the battery and see if the code reappears

  9. 9. Update or Reprogram Modules

    In some cases, the vehicle's software may need to be updated or reprogrammed. Check with the manufacturer for any available updates

  10. 10. Check for Environmental Factors

    Ensure that there are no environmental factors affecting the CD player, such as moisture or extreme temperatures

  11. 11. Consult Technical Service Bulletins (TSBs)

    Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to the U1155 code

  12. 12. Seek Professional Help

    If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with automotive electronics and communication systems. By following these troubleshooting steps, you can systematically identify and address the underlying cause of the U1155 code