Bobcat T770 AUX and Main No Communication Error Troubleshooting

[MikePhua]

On the panswork forum, a user reported an issue with their Bobcat T770, where the equipment displayed "AUX NO COM" and "MAIN NO COM" codes, indicating a loss of communication between the auxiliary and main control systems. This issue led to the machine being unable to function properly. Here is a summary of the problem, its possible causes, and potential solutions.
Problem Description
The user noticed that when operating the Bobcat T770, the display showed “AUX NO COM” and “MAIN NO COM” codes, meaning there was no communication between the auxiliary control system and the main control system. This typically points to a communication breakdown within the machine's electronic control systems, which affects its functions and operation.
Possible Causes

1. Communication Line Fault
   The most common cause of communication failure is a fault in the communication lines. There may be a broken, loose, or interfered connection between the control modules and the equipment. Poor or damaged connections can result in communication failure, triggering the error codes.
   
2. Low Battery Voltage
   Low battery voltage or insufficient power can cause the equipment's electrical control system to malfunction, which can lead to communication failure. If the voltage is unstable, it will affect the control system's operation, causing the "no communication" error.
   
3. Faulty Control Module
   If the main control module (ECM) or the auxiliary control module (AUX ECM) in the Bobcat T770 fails, it can result in a communication breakdown. A damaged or malfunctioning control module may not be able to exchange data with other systems, leading to the “no communication” error codes.
   
4. Software or Firmware Issues
   In some cases, incorrect software or firmware updates can cause issues with the control system's operation. Incompatible versions or incorrect system configurations might disrupt communication.
   
5. Sensor or Connector Issues
   Sometimes, a sensor or connector issue in the control system can cause communication failure. If a sensor stops working or a connector becomes loose, it can affect the signal transmission, leading to the communication error.
   

Solutions

1. Inspect Communication Lines and Connections
   First, check all communication lines between the main control module and the auxiliary control module. Ensure that the cables are securely connected and free from corrosion or damage. If there are any issues with the lines, repair or replace them as needed.
   
2. Check Battery Voltage and Power Supply
   Measure the battery voltage to ensure it is sufficient. If the voltage is too low, charge the battery or replace it. Ensure that the power supply system is stable to prevent voltage fluctuations from affecting the equipment’s performance.
   
3. Check the Control Modules
   If the communication lines and battery are fine, inspect the main and auxiliary control modules. Use a diagnostic tool to read the fault codes from the control modules and check for any hardware issues. If a module is found to be faulty, it may need to be replaced or repaired.
   
4. Update Software and Firmware
   If the issue is related to software or firmware, try reinstalling or updating the software and firmware of the control system. Ensure that all system versions and configurations are compatible with the machine.
   
5. Check Sensors and Connectors
   Inspect all sensors and connectors in the control system to ensure they are not damaged, loose, or corroded. If any issues are found, clean or replace the faulty components.
   

Conclusion
The "AUX NO COM" and "MAIN NO COM" error codes on the Bobcat T770 indicate a communication issue within the machine's systems. By inspecting the communication lines, battery voltage, control modules, software/firmware, and sensors/connectors, you can effectively diagnose and resolve the problem. Keeping the control and electrical systems in good condition will ensure the machine operates efficiently and reliably.