My Check Engine Light came on. The auto parts store said my oxygen sensor was overheating. I put seafoam in the gas to clean out the system and the light is still on.
I think what you are talking about is an oxygen sensor (O2) heater malfunction. Modern O2 sensors use a heater element with a dedicated circuit to bring the sensor up to operating temperature quickly. Once at operating temperature, the powertrain control module (PCM) can use the O2 sensor input to enable more precise fuel control. Most of the time, a O2 sensor heater code is caused by a failed O2 sensor. However, the problems with the heater circuit or PCM could also cause this code. A professional, such as one from YourMechanic, will be able to inspect your vehicle to determine the cause of the Check Engine Light and diagnose why your oxygen sensor is overheating.