U1574 – Module Communication Fault

The ODBII code U1574 indicates a “Module Communication Fault,” meaning there is a communication issue between the vehicle’s control modules, which may affect their ability to exchange data properly.

The severity of ODBII code U1574 is moderate.

Common Causes For: U1573 U1573: “Module Communication Failure”

• Faulty wiring or connectors
• Failed control module
• Corroded or damaged pins
• Poor ground connections
• Intermittent communication issues
• Software or firmware issues
• Electrical interference
• Low battery voltage or power supply issues

Common misdiagnosis for U1574 U1574: “Module Communication Fault”

• Faulty wiring or connectors
• Defective control module
• Software issues or outdated firmware
• Battery or power supply problems
• Grounding issues
• Intermittent communication faults
• Other communication protocol errors

Common Troubleshooting Steps

The OBD-II code U1574 indicates a “Module Communication Fault,” 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 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 for 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 powered correctly, it may not communicate with other modules.
• Perform a Network Scan:
• Use a scan tool capable of performing a network scan to identify which modules are communicating and which are not.
• This can help pinpoint the specific module that is causing the communication fault.
• Inspect the CAN Bus:
• If the vehicle uses a Controller Area Network (CAN) bus, check for issues with the bus itself. Look for short circuits, open circuits, or any other faults in the wiring.
• You can use an oscilloscope to check the signal integrity on the CAN bus.
• Check for Software Updates:
• Sometimes, communication issues can be resolved with a software update. Check with the vehicle manufacturer for any available updates for the affected modules.
• Reset the Modules:
• Disconnect the battery for a few minutes to reset the modules. Reconnect the battery and see if the code returns.
• Alternatively, you can use a scan tool to clear the codes and see if they come back.
• Test the Affected Module:
• If you have identified a specific module that is not communicating, you may need to test or replace that module.
• In some cases, reprogramming or reconfiguring the module may be necessary.
• Consult Technical Service Bulletins (TSBs):
• Check for any TSBs related to the U1574 code for your specific vehicle make and model. Manufacturers may have specific recommendations for addressing this issue.
• Seek Professional Help:
• If you are unable to resolve the issue after performing these steps, it may be best to consult a professional mechanic or technician who has experience with automotive electronics and communication systems. By following these steps, you should be able to diagnose and potentially resolve the U1574 code. Always refer to the vehicle’s service manual for specific procedures and specifications related to your vehicle.