1999 Toyota corolla- catalytic converter error code

[bennyandthejets]

Bottom line – stay away from the dealer. You didn’t have both the CAT and sensors go bad at the same time. Most shops can read your sensors with a scan tool to see how they’re performing. A simple digital thermometer with a laser light that points at the CAT will tell if it is working or not. The hand held model that you shine the laser at and it gives you a temp. can be bought at Harbor Freight for 49 bucks. The back of the converter should be hotter than the front of the converter. If that is the case, it is burning (working). If they are about the same temp, it is old and used up. Make sure the car is good and warmed up first. At 149K miles, it might be used up. The material inside doesn’t have an unlimited lifetime, it will wear out eventually. I had a CAT on my Sentra several years ago that quit working at about 150K miles but never gave me an indication because it was a carburated car, and it burned so clean it always passed emissions test, even at the 300K mile mark when I sold it. The Autozones here in Utah use a scan tool that will read dynamic O2 sensor voltages. Basically you’re looking for a lot of activity (voltages fluxing up and down from .100 - .900 V) with the sensor(s) prior to the CAT and not much activity (minimal voltage changes) post CAT. They can also do an O2 sensor readiness test, and the best part is that it is all free at autozone, schuks, etc. The hard part is finding a counter person that knows how to read the scan tool well and knows what everything means. Don’t spend the kind of money the dealer wants, I’m betting if you were to get the same parts replaced in a muffler shop, it would be 1/4 to 1/3 as much. Good luck.