This code means that the catalytic converter in your car is not working properly. The catalytic converter is a device that helps to reduce emissions from your car's engine. It does this by converting harmful pollutants into less harmful gases.
When the catalytic converter is not working properly, it can cause your car to fail emissions tests. It can also damage the engine and other components of your car's exhaust system.
If you see the P0436 code, you should have your car diagnosed by a qualified mechanic as soon as possible.
