I had a catalystic convertor put on and I am still getting O2 sensor error.What could be the problem?


Asked by Jul 01, 2013 at 09:09 PM about the 1997 Mitsubishi Montero Sport 4 Dr LS 4WD SUV

Question type: Maintenance & Repair

I  h ad a catalytic convertor put on  and I am still getting O2 sensor error. What could be the problem? It is not giving a readiness for emission test.

6 Answers

Daniel Foster

did you check your exhaust all the way to the manifold for leaks or check your O2 sensors to see that their working correctly ? get your car scanned and post some codes so we have some thing to work with, can get it done for free at advance auto or autozone or some other places do it but I know those do it for sure

1 out of 1 people think this is helpful.
Michael Tutty

If it says oxygen sensor error, you need a new sensor, or if the car has more than one, change all of them. Bad oxygen sensor(s) will cause the new catalytic converter to fail in fairly short order, too. In fact, they are the main reason catalytic converters fail in the first place.


Thanks, the shop that put the converter on checked everything to find out which converter was bad, so I assume that they checked the O2 senors, also.

Daniel Foster

get some codes already lol

Michael Tutty

You said the codes showed a bum sensor, so you need to change the sensor. Also, the sensor could well be dirty, and misreading, which causes a run rich situation and that is the number one cause of catalytic converter failure. Also, if you have more than one cat, are they in line, or is this a V engine with a cat or two on each bank> If you have a V engine, with separate cats for each bank, CHANGE BOTH AT THE SAME TIME! Not doing so results in uneven back pressure. That leads to burned valves very quickly. That means new heads at a minimum, and possibly a full rebuild. Only doing half a repair is penny wise and pound foolish.

1 out of 1 people think this is helpful.

My car continues to fail during my annual inspection because of OBD results: PO158 02, PO137 , and PO141 02. Could it be my Catalystic converta. What do you suggest I do first.

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