Based on the information you provided, it is possible that the check engine light in your 2015 Ford Explorer is related to the oxygen (O2) sensors. O2 sensors play a crucial role in monitoring the exhaust gases to ensure optimal fuel efficiency and reduced emissions. If the sensors are faulty or not functioning properly, it can trigger the check engine light.

Since the catalytic converters were replaced recently, it is unlikely that they are causing the issue. However, it could be worth checking if there are any underlying issues with the O2 sensors that are causing them to malfunction.

When the check engine light came on, it is likely that the O2 sensors were reading a problem and stored a corresponding trouble code in the car's computer system. This code can be retrieved using an OBD-II scanner, which provides more specific information about the problem.

I would recommend taking your vehicle to a professional mechanic or an automotive parts store that offers code reading services. They will be able to scan the trouble codes and provide you with a more accurate diagnosis of the issue. Once you know the specific trouble code, it will be easier to determine the root cause and appropriate steps for a solution.

In the meantime, you can check if there are any obvious signs of damage or loose connections around the O2 sensor wiring. They are typically located on the exhaust system, both before and after the catalytic converters. If you notice anything amiss, such as frayed wires or loose connections, you may be able to address the issue yourself. However, keep in mind that unless you have proper knowledge and tools, it is best to leave any major repairs or replacements to a professional mechanic.

Overall, while it is possible that the check engine light is related to the O2 sensors, further diagnosis of the specific trouble codes is necessary before reaching a definitive conclusion.