U1743 – Module Communication Failure

The ODBII code U1743 indicates a “Module Communication Failure,” meaning there is a problem with communication between vehicle control modules, often due to a wiring issue, a faulty module, or a network problem.

The severity of ODBII code U1743 is generally considered moderate.

Common Causes For: U1742 U1742: “Module Communication Failure”

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

Common misdiagnosis for U1743 U1743: “Module Communication Failure”

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

Common Troubleshooting Steps

The OBD-II code U1743 indicates a “Module Communication Failure,” which typically means that there is a problem with communication between the vehicle’s control modules. 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 module(s). 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 Power Supply: Ensure that the affected module is receiving the proper voltage. Use a multimeter to check the power and ground circuits.
• Test the Module: If possible, test the affected module to see if it is functioning correctly. This may involve bench testing or swapping with a known good module.
• Check for Intermittent Issues: Sometimes, communication failures can be intermittent. Try to replicate the conditions under which the code was set, and monitor the communication between modules.
• Inspect the CAN Bus: If the vehicle uses a Controller Area Network (CAN) for communication, check the integrity of the CAN bus. Look for short circuits, open circuits, or noise on the bus.
• Update Software/Firmware: Check if there are any software or firmware updates available for the vehicle’s modules. Sometimes, communication issues can be resolved with an update.
• Clear Codes and Test Drive: After performing any repairs or inspections, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Service Manual: Refer to the vehicle’s service manual for specific diagnostic procedures related to the U1743 code and the modules involved.
• Professional Diagnosis: If the issue persists after performing the above steps, consider seeking help from a professional mechanic or dealership with experience in diagnosing communication issues. By following these steps, you should be able to identify and resolve the underlying cause of the U1743 code.