U1722 – Module Communication Failure

The ODBII code U1722 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 U1722 is moderate.

Common Causes For: U1721 U1721: Transmission Control Module Communication Error

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

Common misdiagnosis for U1722 U1722: “Module Communication Failure”

• Faulty wiring or connectors
• Defective control modules
• Software issues or updates needed
• Power supply problems
• Grounding issues
• Intermittent communication faults
• Incorrectly configured or programmed modules

Common Troubleshooting Steps

The OBD-II code U1722 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 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 modules. 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 voltage and ground continuity.
• If the module is not receiving power, trace the wiring back to the fuse box and check for blown fuses or damaged wires.
• Test the Module:
• If possible, test the affected module by swapping it with a known good module (if available) to see if the problem persists.
• Some modules may have built-in self-diagnostic capabilities that can provide additional information.
• Check for Communication:
• Use a scan tool to check if the affected module is communicating with other modules. If it is not, there may be a fault in the module itself or in the communication network.
• Verify that the communication protocols (e.g., CAN, LIN) are functioning correctly.
• Inspect the CAN Bus:
• If the vehicle uses a CAN bus system, check for issues with the bus itself. Look for short circuits, open circuits, or excessive resistance in the CAN wiring.
• Use an oscilloscope to monitor the CAN signals if you have access to one.
• 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.
• Clear Codes and Test Drive:
• 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):
• Look for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on known communication issues.
• Seek Professional Help:
• If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle and its systems. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U1722 code.