Today I noticed my car wasn't accelerating like it should have been and thankfully when I was pulling up to my house my car was not accelerating at all my VSA light came on. I waited a few mins got back into my car and the VSA light went off and it was accelerating I made it to autozone and the code they gave me was P0420. I understand that maybe for my catalytic converter but I was reading about this problem somewhere else and it was suggested I change my app sensor. I would like to try doing the work myself and wanted to know if I should first start with the app sensor. Thank you!!

 

Did your car limit how fast you could go? Usually if it is the APP sensor, your car would've gone into limp mode, which is a max of 20 mphs I think.

 

Yes I started to accelerate at 15 and once it got to 20 it stopped accelerating

 

Replacing the APP sensor should fix the problem. Remember to clear the code after it has been replaced.

 

Could it be possible my app sensor threw the code for my catalytic converter? The other day it gave me a code for my throttle sensor and cat.

 

I have no clue. I know that if the car goes into limp mode with the CEL/VSA light, the most common culprit is the APP sensor.