Use a multimeter to check the resistance of the EEV coil. If the ohms are outside the manufacturer's specified range (usually around 40-50 ohms depending on the model), the coil needs replacement.
If basic troubleshooting fails, the following technical steps are required: o general ac error code 9c
This article breaks down what error code 9c means, why it happens, and how you can resolve it. What is O General AC Error Code 9c? Use a multimeter to check the resistance of the EEV coil
In some cases, extreme pressure imbalances can trigger sensor errors that mimic an EEV trip. Step-by-Step Troubleshooting What is O General AC Error Code 9c
If you are comfortable opening the unit, ensure the wire harness connecting the indoor unit to the outdoor unit is secure. A loose communication wire is a frequent culprit for "9" series errors in O General models. Technical Solutions for Professionals