WOMS
U code network Medium severity

U1207 SCP (J1850) Invalid or Missing Data for Primary Id

The OBD2 code U1207 SCP (J1850) indicates that there is invalid or missing data from the primary identifier in the vehicle's communication network, which may affect the operation of various systems

Definition

The OBD2 code U1207 SCP (J1850) indicates that there is invalid or missing data from the primary identifier in the vehicle's communication network, which may affect the operation of various systems

Common causes

  • Faulty or damaged wiring/connectors
  • Malfunctioning control modules
  • Poor ground connections
  • Communication network issues
  • Corrupted data or software glitches
  • Incompatible or faulty aftermarket devices
  • Low battery voltage or power supply issues
  • Interference from other electronic devices

Common misdiagnoses

  • Faulty ABS module
  • Defective engine control module (ECM)
  • Bad wiring or connectors
  • Malfunctioning body control module (BCM)
  • Incorrectly programmed or flashed modules
  • Faulty communication lines
  • Issues with the vehicle's battery or charging system
  • Problems with the instrument cluster

Troubleshooting steps

  1. 1. Check for Additional Codes

    Use an OBD-II scanner to check for any other trouble codes that may be present. Addressing other codes may resolve the U1207 issue

  2. 2. Inspect the Wiring and Connectors

    Visual Inspection: Check the wiring harnesses and connectors related to the affected modules for any signs of damage, corrosion, or loose connections

  3. 3. Repair or Replace

    Repair any damaged wires or connectors as necessary

  4. 4. Check the Battery and Ground Connections

    Ensure that the vehicle's battery is fully charged and that all ground connections are clean and secure. Poor ground connections can lead to communication issues

  5. 5. Test the Modules

    Module Functionality: Verify that the primary module (often the PCM or another control module) is functioning correctly. This may involve checking for proper operation or testing the module with a scan tool

  6. 6. Communication Test

    Use a scan tool to check if the affected module is communicating with other modules on the network

  7. 7. Inspect the SCP Bus

    Bus Integrity: Check the integrity of the SCP bus wiring. Look for shorts, opens, or high resistance in the communication lines

  8. 8. Signal Quality

    Use an oscilloscope to check the signal quality on the SCP bus. Look for any irregularities in the waveform

  9. 9. Check for Interference

    Ensure that there are no aftermarket devices or modifications that could be interfering with the SCP communication

  10. 10. Perform a Hard Reset

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

  11. 11. Update Software/Firmware

    Check if there are any software updates available for the vehicle's control modules. Sometimes, manufacturers release updates to fix communication issues

  12. 12. Consult Technical Service Bulletins (TSBs)

    Look for any TSBs related to the U1207 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known fixes

  13. 13. Professional Diagnosis

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership. They may have specialized tools and knowledge to diagnose complex communication issues. By following these troubleshooting steps, you should be able to identify and resolve the underlying issue causing the U1207 code