U1535 – Module Communication Failure

The ODBII 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.

The severity of ODBII code U1535 is moderate.

Common Causes For: U1534 U1534: “Module Communication Failure”

• 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 misdiagnosis for U1535 U1535: “Module Communication Failure”

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

Common Troubleshooting Steps

The OBD-II code U1535 indicates a “Module Communication Failure,” which typically means that there is a problem with communication between various modules in the vehicle’s network. Here are some common troubleshooting steps to diagnose and resolve this issue:

• 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.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the affected modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the ground connections, as poor grounding can lead to communication issues.
• Check Module Power Supply:
• Ensure that the affected modules are receiving the proper voltage and ground. Use a multimeter to check the power supply to the modules.
• If a module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wiring.
• Test Communication Lines:
• Use a scan tool to check the communication lines (CAN bus, LIN bus, etc.) for continuity and proper signal levels.
• If you have access to an oscilloscope, you can use it to monitor the communication signals for abnormalities.
• Inspect for Interference:
• 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.
• Reset the Modules:
• 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.
• Update or Reprogram Modules:
• 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.
• Check for Water Intrusion:
• Inspect areas where modules are located for signs of water intrusion, which can cause corrosion and communication failures.
• Replace Faulty Modules:
• 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.
• Consult Technical Service Bulletins (TSBs):
• 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
• Professional Diagnosis:
• 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.