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U code network High severity

U1336 Manufacturer Specific" code, which typically indicates an issue related to the communication between modules in the vehicle's network

The OBD2 code U1336 indicates a communication issue between modules in the vehicle's network, often related to a fault in the data bus or a specific module's failure to communicate properly

Definition

The OBD2 code U1336 indicates a communication issue between modules in the vehicle's network, often related to a fault in the data bus or a specific module's failure to communicate properly

Common causes

  • Faulty wiring or connectors in the communication network
  • Malfunctioning control modules
  • Corrupted software or firmware in one or more modules
  • Poor ground connections
  • Interference from aftermarket accessories
  • Low battery voltage or weak battery
  • Faulty or damaged CAN bus

Common misdiagnoses

  • Faulty wiring or connectors
  • Defective control modules
  • Battery or charging system issues
  • Software glitches or outdated firmware
  • Grounding problems
  • Intermittent electrical connections
  • Faulty sensors unrelated to communication
  • Incorrectly installed aftermarket accessories
  • Corrupted data in the vehicle's network
  • Issues with the OBDII scanner or diagnostic tool

Troubleshooting steps

  1. 1. Check for Other Codes

    Use an OBD-II scanner to check for any additional trouble codes. Addressing other codes may resolve the U1336 code

  2. 2. Inspect Wiring and Connectors

    Visual Inspection: Check the wiring and connectors related to the modules involved in the communication. Look for signs of damage, corrosion, or loose connections

  3. 3. Repair or Replace

    Repair any damaged wires or connectors and ensure all connections are secure

  4. 4. Check Module Functionality

    Module Status: Verify that all modules in the vehicle are functioning correctly. If a specific module is malfunctioning, it may cause communication issues

  5. 5. Reprogram or Replace

    If a module is found to be faulty, consider reprogramming or replacing it

  6. 6. Inspect the CAN Bus

    CAN Bus Integrity: Check the integrity of the Controller Area Network (CAN) bus. Look for shorts, opens, or high resistance in the bus lines

  7. 7. Termination Resistors

    Ensure that the termination resistors at both ends of the CAN bus are present and functioning correctly

  8. 8. Check Power and Ground

    Power Supply: Verify that all modules have the correct power supply. Use a multimeter to check voltage levels

  9. 9. Ground Connections

    Ensure that all ground connections are clean and secure

  10. 10. Perform a Network Test

    Use a scan tool capable of performing a network test to check for communication between modules. This can help identify which module is not communicating properly

  11. 11. Clear Codes and Test Drive

    After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner

  12. 12. Take the vehicle for a test drive to see if the code reappears

  13. 13. Consult Manufacturer Documentation

    Refer to the vehicle’s service manual or manufacturer-specific documentation for any additional troubleshooting steps or specific procedures related to the U1336 code

  14. 14. Seek Professional Help

    If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing communication issues in your specific vehicle make and model. By following these steps, you can systematically diagnose and potentially resolve the issue related to the U1336 OBD-II code