Q: I have a 2010 Honda CR-V. Last month its check engine light came on. I’m a retired mechanic and, using my diagnostic scanner, found a trouble code of P0420, which indicates an issue with catalytic ...

Q: I have a 2010 Honda CR-V. Last month its check engine light came on. I'm a retired mechanic and my scanner found code P0420 — catalytic converter efficiency. I tried a catalytic converter cleaner.

Thanks to modern fuel injection, the engine computer has extremely precise control over the proportions of the air/fuel mixture inside the cylinders. A countless number of sensors around the car tell ...

Question:I have a 2001 Nissan Pathfinder with the 3.5-liter V-6. The check-engine light came on, and I had code P0420. I was told it was a bad catalytic converter, so I went ahead and replaced it ...