U1538 – Module Communication Failure

The ODBII code U1538 indicates a communication failure between modules in the vehicle’s network, suggesting that one or more electronic control units (ECUs) are unable to communicate properly with each other.

The severity of ODBII code U1538 is generally considered moderate to severe.

Common Causes For: U1537 U1537: “Module Communication Failure”

• Faulty wiring or connectors
• Failed or malfunctioning module
• Corrupted software or firmware
• Poor ground connections
• Interference from aftermarket devices
• Low battery voltage
• Communication network issues (e.g., CAN bus problems)

Common misdiagnosis for U1538 U1538: “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 in the network

Common Troubleshooting Steps

The OBD-II code U1538 indicates a “Module Communication Failure,” which typically means that there is a problem with communication between various modules in the vehicle’s network. 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: Examine the wiring and connectors associated with the affected modules. Look for signs of damage, corrosion, loose connections, or broken wires. Pay special attention to ground connections.
• Verify Module Functionality: Ensure that the module(s) involved in the communication are functioning properly. This may involve checking for power and ground at the module connectors.
• 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 modules.
• Perform a Network Scan: Use a professional-grade scan tool to perform a network scan. This can help identify which module is not communicating properly.
• Inspect the CAN Bus: If your vehicle uses a Controller Area Network (CAN) bus, check for issues with the bus itself. Look for short circuits, open circuits, or other faults in the CAN wiring.
• Test Modules Individually: If possible, test the modules individually to see if they are functioning correctly. This may involve bench testing or swapping with known good modules.
• Check for Interference: Ensure that there are no aftermarket devices or modifications that could be causing interference with the vehicle’s communication network.
• Clear Codes and Test Drive: After performing any repairs or adjustments, clear the trouble codes and take the vehicle for a test drive to see if the code returns.
• Consult Technical Service Bulletins (TSBs): Check for any TSBs related to the specific make and model of your vehicle. Manufacturers may have issued guidance on common communication issues. 1
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or dealership for further diagnosis and repair. By following these steps, you can systematically identify and resolve the underlying cause of the U1538 code.