U1735 – Module Communication Failure

The ODBII code U1735 indicates a “Module Communication Failure,” meaning there is a problem with communication between the vehicle’s control modules, often due to a wiring issue, a faulty module, or a network problem.

The severity of ODBII code U1735 is moderate.

Common Causes For: U1734 U1734: “Module Communication Failure”

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

Common misdiagnosis for U1735 U1735: “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 U1735 indicates a “Module Communication Failure,” which typically means that there is a communication issue between the vehicle’s control modules. Here are some common troubleshooting steps to diagnose and resolve this issue:

• Check for Other 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 module(s). Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harnesses that connect the modules, as these can be prone to wear and tear.
• Check Power and Ground:
• Ensure that the affected module has a proper power supply and ground connection. Use a multimeter to check for voltage at the module’s power and ground pins.
• If there is no power or ground, trace the wiring back to the source to identify any breaks or shorts.
• Test the Module:
• If possible, test the affected module to ensure it is functioning correctly. This may involve swapping it with a known good module or using a diagnostic tool to perform a module self-test.
• If the module is faulty, it may need to be repaired or replaced.
• Check for Communication:
• Use a scan tool to check if the affected module is communicating with other modules in the network. If it is not, there may be a fault in the communication lines (CAN bus, LIN bus, etc.).
• You can also use a scope or a scan tool with live data capabilities to monitor communication signals.
• Inspect the CAN Bus:
• If the vehicle uses a CAN bus for communication, check for any issues with the bus itself. Look for short circuits, open circuits, or interference that could disrupt communication.
• You may need to check the termination resistors and ensure they are functioning correctly.
• Reset the Codes:
• After performing the above checks and repairs, clear the trouble codes using the OBD-II scanner and take the vehicle for a test drive to see if the code returns.
• Consult Technical Service Bulletins (TSBs):
• Check for any manufacturer-specific TSBs related to the U1735 code. There may be known issues or recalls that could provide additional guidance.
• Seek Professional Help:
• If you are unable to resolve the issue after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific make and model of your vehicle. By following these troubleshooting steps, you should be able to identify and resolve the underlying cause of the U1735 code.