P0420 Jeep -

Question

My check engine light came on after fuel injection cleaning. I reset it by disconnecting the battery but it came back on a day later.

Answer 1

Hi there,

Sometimes the cleaner can cause the catalytic converter code to appear. I would run the truck a few days with the light on if it's running ok, then clear the code and see if it returns. If it does, then it's possible you are going to need to replace the converter.