U2959 – Lost Communication with Vehicle Control Module.

The ODBII code U2959 indicates a loss of communication with the vehicle control module, suggesting that the module is not responding or is unable to communicate with other systems in the vehicle.

The severity of ODBII code U2959 is generally considered moderate to high.

Common Causes For: U2958 Lost Communication with the Hybrid Powertrain Control Module (HPCM) A.

• Faulty wiring or connectors
• Failed Vehicle Control Module (VCM)
• Corroded or damaged connectors
• Poor ground connections
• Malfunctioning communication network (CAN bus)
• Software issues or bugs in the VCM
• Interference from aftermarket devices
• Low battery voltage or power supply issues

Common misdiagnosis for U2959 Lost Communication with Vehicle Control Module.

• Faulty Vehicle Control Module (VCM)
• Wiring issues or shorts in the communication lines
• Faulty connectors or terminals
• Issues with other control modules (e.g., Engine Control Module, Transmission Control Module)
• Battery or power supply problems
• Corrupted software or firmware in the control modules
• Faulty sensors that affect communication
• Grounding issues in the electrical system

Common Troubleshooting Steps

The OBD-II code U2959 indicates a “Lost Communication with Vehicle Control Module.” This code typically suggests that there is a communication issue between the vehicle’s control modules, which can be caused by various factors. Here are some common troubleshooting steps to help diagnose and resolve the issue:

• Check for Other Codes: Use an OBD-II scanner to check for any additional trouble codes. Other codes may provide more context or indicate related issues.
• Inspect Wiring and Connectors:
• Visually inspect the wiring and connectors associated with the affected control module. Look for signs of damage, corrosion, or loose connections.
• Pay special attention to the wiring harnesses that connect to the control modules.
• Check Power and Ground:
• Ensure that the control module has proper power and ground connections. Use a multimeter to check for voltage at the module’s power supply pins and continuity at the ground pins.
• If there is no power or ground, trace the wiring back to the fuse box or battery to identify the issue.
• Test the Control Module:
• If possible, test the control module itself. This may involve using a scan tool to communicate with the module or swapping it with a known good module if available.
• Ensure that the module is functioning correctly and is not damaged.
• Check for Communication Issues:
• Use a scan tool to check if other modules in the vehicle can communicate. If other modules are also unresponsive, it may indicate a network issue.
• Inspect the CAN (Controller Area Network) bus wiring for shorts, opens, or interference.
• Inspect Fuses:
• Check the fuses related to the control modules and communication systems. Replace any blown fuses and retest.
• Look for Software Updates:
• Check if there are any software updates available for the vehicle’s control modules. Sometimes, communication issues can be resolved with a software update.
• Perform a Hard Reset:
• Disconnect the vehicle’s battery for a few minutes to reset the control modules. Reconnect the battery and see if the code reappears.
• 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 the above steps, consider seeking assistance from a qualified technician or automotive professional 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 U2959 code.