When the Midea Coolwind** air conditioner screen displays UL00, it usually means that there is a communication failure in the air conditioning system. This fault may involve many aspects such as the communication line, communication module, or control board between the indoor unit and the outdoor unit. In order to solve this problem, you can try the following decoding and repair steps:
First, you can try powering off and restarting. Turn off the power on the air conditioner and wait a few minutes before turning it back on. This helps resolve communication failures caused by sporadic system errors.
If the problem persists after the power is off and restarted, you need to check the communication line between the indoor unit and the outdoor unit. Check the line for aging, damage, or poor connections. If there is a problem, the line needs to be replaced or repaired in time. If there is no problem with the communication line, then the communication module of the indoor unit and the outdoor unit needs to be further checked. You can use professional inspection tools to test the communication module, and if a fault is found, you need to replace the corresponding module. 
If none of the above steps resolve the issue, then there may be a malfunction in the control board. You need to perform a detailed inspection of the control board, including checking whether the components on it are damaged, whether the connection is good, etc. If a problem is found with the control board, it needs to be replaced with a new one or repaired. When dealing with air conditioner communication failures, stay calm and follow the steps to troubleshoot the problem one by one. If you're not sure how to do this, you can seek professional help. 
Due to the complexity and professionalism of the air conditioning system, it is recommended to contact professional maintenance personnel for handling when encountering UL00 failure**. Do not disassemble or repair the air conditioning system at will to avoid greater losses or safety risks. In addition, in order to avoid the occurrence of similar failures, it is recommended to carry out regular service and maintenance of the air conditioning system, including cleaning dust and dirt, checking the working condition of wiring and components, etc. At the same time, pay attention to the influence of the use environment on the air-conditioning system, keep the air-conditioning system well ventilated, and use a stable power supply.