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.
Answer:That's a new one for me, and I cannot see it having any effect on preventing a P0420 DTC, but it is illegal. P0420 indicates the catalytic converter has lost its efficiency in reducing harmful ...