I have two older vehicles I drive about about once a week. A 1996 Toyota Tacoma with 180k miles and a 2005 Hyundai Santa Fe with 150k miles. My primary vehicle is a 2017 Toyota Tacoma.
Both my 1996 Tacoma and 2005 Hyundai Santa Fe have had the P0420 (Catalyst Efficiency Below Threshold) code for over 8 months. I’ve cleared the code several times with my OBD2 reader to clear the check engine light, and the CEL usually returns within a week or two.
Replacing the catalytic converter on these vehicles will cost more than the vehicles are worth. I would like to keep the vehicles for a few more years if possible. I haven’t noticed any issues other than the CEL light and the P0420 code. Could driving these vehicles with a possible bad catalytic converter damage the engine? Or is it mostly emissions that are affected? I live in a state where emissions are not tested. I cleared the CEL with the OBDII reader prior to their last state inspection several months ago.