Common Daikin Air Conditioning Fault Codes A1 - Micro-computer in PCB is not working - this is a fault that occurs either in the assembly of the PCB or due to an external factor, such as noise. A3 - Drain level is too high - This is caused by a clogging of dirt in the drain, or a faulty drain pump. Daikin fault codes are a vital diagnostic tool for identifying system errors in Daikin air conditioning systems. These alphanumeric codes provide technicians with valuable information to pinpoint and rectify issues quickly, ensuring efficient and reliable operation of the equipment. System error codes. Daikin Error code u0- Shortage of refrigerant. Probable causes: Refrigerant shortage and/or refrigerant clogging (wrong piping) Defective Daikin thermistor; Defective low-pressure sensor; Defective outdoor unit's main PCB; Error U1- Reverse phase, open phase. Probable causes: Power supply reverse phase; T- phase open phase Find out more in your region. Error Code Search offers information on the cause of the malfunction and the status of your air conditioner by entering the error code. Daikin | wireless remote | how to check error code. (ceiling cassette) Brand : Daikin (super inverter) indoor : ceiling cassette. error code : C4 Indoor gas pipe thermistor faulty. 1. Select the product group Split/Multi-Split Air Purifiers Others 2. Select a trouble Does not cool/warm Does not operate Does not operate immediately Operation stops Operation does not stop Abnormal sound during operation Abnormal sound during filter cleaning Abnormal sound In non-operation Odor Cleaning Remote controller j95056.