U2537 – Communication Bus Off.

The ODBII code U2537 indicates a communication issue where a module on the vehicle’s communication bus has gone offline or is not responding, potentially due to a fault in the network or a malfunctioning module.

The severity of ODBII code U2537 is moderate to severe.

Common Causes For: U2535 U2535: Vehicle Communication Bus Malfunction

• Faulty communication module
• Damaged wiring or connectors
• Short circuit in the communication bus
• Open circuit in the communication bus
• Software or firmware issues
• Low battery voltage
• Interference from aftermarket devices
• Faulty sensors or actuators on the bus

Common misdiagnosis for U2537 Communication Bus Off.

• Faulty ABS module
• Defective engine control module (ECM)
• Malfunctioning transmission control module (TCM)
• Wiring issues or shorts in the communication lines
• Bad ground connections
• Faulty sensors or actuators
• Incorrectly diagnosed battery or charging system issues
• Issues with the body control module (BCM)

Common Troubleshooting Steps

The OBD-II code U2537 indicates a communication issue related to the vehicle’s communication bus, specifically that a module is reporting a “Bus Off” condition. This typically means that a module on the communication network is unable to communicate properly, often due to a fault in the wiring, a malfunctioning module, or interference on the bus. 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. Codes related to other modules can provide clues about the source of the problem.
• Inspect Wiring and Connectors: Visually inspect the wiring and connectors associated with the communication bus (CAN bus, LIN bus, etc.). Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the connectors of the modules involved in the communication.
• Check for Short Circuits or Open Circuits: Use a multimeter to check for continuity in the communication lines. Look for any short circuits or open circuits that could be causing the communication failure.
• Test the Modules: Identify the modules on the communication bus and test them individually if possible. This may involve checking for power and ground at the module connectors.
• If a specific module is suspected to be faulty, consider replacing or reprogramming it.
• Inspect for Interference: Check for any aftermarket devices or modifications that may be interfering with the communication bus. This includes alarms, stereo systems, or other electronic devices.
• Check Battery Voltage and Ground: Ensure that the vehicle’s battery is fully charged and that all ground connections are secure. Low voltage or poor grounding can cause communication issues.
• Scan for Communication Issues: Use a professional-grade scan tool to monitor the communication bus while the vehicle is running. This can help identify if specific modules are not responding.
• Perform a Network Test: Some advanced scan tools can perform a network test to check the integrity of the communication bus. This can help identify if there are any issues with the bus itself.
• Clear Codes and Test Drive: After performing the above checks and repairs, 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 communication bus and the U2537 code. This may provide additional insights or steps specific to your vehicle model.1
• Seek Professional Help: If the issue persists after performing these steps, it may be necessary to consult a professional mechanic or technician who specializes in automotive electronics. By following these troubleshooting steps, you should be able to identify and resolve the underlying issue causing the U2537 code.