U1523 – Control Module Communication Failure

The ODBII code U1523 indicates a communication failure between control modules in a vehicle, suggesting that one or more modules are not able to exchange data properly.

The severity of ODBII code U1523 is moderate.

Common Causes For: U1522 U1522: “Module Communication Failure”

• Faulty control module
• Poor electrical connections
• Damaged wiring harness
• Corroded connectors
• Software issues or bugs
• Low battery voltage
• Interference from aftermarket devices
• Faulty CAN bus communication
• Grounding issues

Common misdiagnosis for U1523 U1523: “Control Module Communication Failure”

• Faulty control module
• Wiring issues
• Poor ground connections
• Corrupted software/firmware
• Faulty sensors
• Communication network issues
• Battery or power supply problems
• Intermittent connection faults

Common Troubleshooting Steps

The OBD-II code U1523 indicates a “Control Module Communication Failure.” This code typically suggests that there is a problem with communication between the vehicle’s control modules. Here are some common troubleshooting steps to diagnose and resolve the 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 control modules. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harnesses that connect the affected modules.
• Check Power and Ground: Verify that the control module in question is receiving proper power and ground. Use a multimeter to check voltage and ground continuity.
• Ensure that the fuses related to the control modules are intact.
• Test the Control Module: If possible, test the control module itself. This may involve using specialized diagnostic tools or software to check for functionality.
• If the module is faulty, it may need to be reprogrammed or replaced.
• Inspect the CAN Bus: The communication between control modules often occurs over a Controller Area Network (CAN) bus. Check for issues with the CAN bus wiring, such as shorts or opens.
• Use an oscilloscope or CAN bus diagnostic tool to monitor the bus for proper communication signals.
• Check for Interference: Look for any aftermarket devices or modifications that may interfere with the communication between control modules. This includes alarm systems, stereo systems, or other electronic devices.
• 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 source of the communication failure.
• Reset the Control Modules: Sometimes, simply resetting the control modules can resolve communication issues. This can be done by disconnecting the battery for a few minutes or using a scan tool to clear the codes.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the specific make and model of the vehicle. Manufacturers may have issued guidance on common issues related to control module communication.
• Seek Professional Help: If the issue persists after performing the above steps, it may be necessary to consult a professional mechanic or technician who has experience with the specific vehicle and its control systems. By following these troubleshooting steps, you can systematically identify and resolve the underlying cause of the U1523 code.