U1535: U1535: "Module Communication Failure

Definition

The OBD2 code U1535 indicates a communication failure between modules in a vehicle's network, suggesting that one or more electronic control units (ECUs) are not able to communicate properly with each other

Common causes

Faulty wiring or connectors
Failed or malfunctioning module
Corroded or damaged pins
Poor ground connections
Intermittent electrical issues
Software or firmware issues
Low battery voltage or power supply problems
Communication network issues (e.g., CAN bus problems)

Common misdiagnoses

Faulty wiring or connectors
Defective control module
Software issues or updates needed
Power supply problems
Grounding issues
Intermittent communication issues
Other communication protocol failures

Troubleshooting steps

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. Inspect Wiring and Connectors
3. Visually inspect the wiring and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections
4. Pay special attention to the ground connections, as poor grounding can lead to communication issues
5. Check Module Power Supply
6. Ensure that the affected modules are receiving the proper voltage and ground. Use a multimeter to check the power supply to the modules
7. If a module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wiring
8. Test Communication Lines
9. Use a scan tool to check the communication lines (CAN bus, LIN bus, etc.) for continuity and proper signal levels
10. If you have access to an oscilloscope, you can use it to monitor the communication signals for abnormalities
11. Inspect for Interference
12. Look for any aftermarket devices or modifications that may interfere with the vehicle's communication network. This includes alarm systems, stereo systems, or other electronic devices
13. Reset the Modules
14. Sometimes, simply resetting the affected modules can resolve communication issues. Disconnect the battery for a few minutes, then reconnect it and see if the code returns
15. Update or Reprogram Modules
16. If the vehicle has had recent software updates or module replacements, ensure that all modules are properly programmed and updated to the latest software version
17. Check for Water Intrusion
18. Inspect areas where modules are located for signs of water intrusion, which can cause corrosion and communication failures
19. Replace Faulty Modules
20. If all other steps fail and a specific module is identified as faulty, it may need to be replaced. Ensure that the replacement module is compatible with your vehicle
21. Consult Technical Service Bulletins (TSBs)
22. Check for any TSBs related to the U1535 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues that can help in troubleshooting. 1
23. Professional Diagnosis
24. If you are unable to resolve the issue, consider seeking help from a professional mechanic or dealership with experience in diagnosing module communication issues. By following these steps, you should be able to identify and resolve the underlying cause of the U1535 code

Definition

Common causes

Common misdiagnoses

Troubleshooting steps

1. Check for Additional Codes

2. Inspect Wiring and Connectors

3. Visually inspect the wiring and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections

4. Pay special attention to the ground connections, as poor grounding can lead to communication issues

5. Check Module Power Supply

6. Ensure that the affected modules are receiving the proper voltage and ground. Use a multimeter to check the power supply to the modules

7. If a module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wiring

8. Test Communication Lines

9. Use a scan tool to check the communication lines (CAN bus, LIN bus, etc.) for continuity and proper signal levels

10. If you have access to an oscilloscope, you can use it to monitor the communication signals for abnormalities

11. Inspect for Interference

12. Look for any aftermarket devices or modifications that may interfere with the vehicle's communication network. This includes alarm systems, stereo systems, or other electronic devices

13. Reset the Modules

14. Sometimes, simply resetting the affected modules can resolve communication issues. Disconnect the battery for a few minutes, then reconnect it and see if the code returns

15. Update or Reprogram Modules

16. If the vehicle has had recent software updates or module replacements, ensure that all modules are properly programmed and updated to the latest software version

17. Check for Water Intrusion

18. Inspect areas where modules are located for signs of water intrusion, which can cause corrosion and communication failures

19. Replace Faulty Modules

20. If all other steps fail and a specific module is identified as faulty, it may need to be replaced. Ensure that the replacement module is compatible with your vehicle

21. Consult Technical Service Bulletins (TSBs)

22. Check for any TSBs related to the U1535 code for your specific vehicle make and model. Manufacturers may have specific recommendations or known issues that can help in troubleshooting. 1

23. Professional Diagnosis

24. If you are unable to resolve the issue, consider seeking help from a professional mechanic or dealership with experience in diagnosing module communication issues. By following these steps, you should be able to identify and resolve the underlying cause of the U1535 code