Catalytic Converter and O2 Sensor both replaced

[Devil's Advocate]

Ok, putting this back in because I think a bunch of people aren't checking it out because I was to vague in the original title.

Hey back again, I took some time getting back after the site collapsed last year.

Well here is an interesting story. I had the Check Engine" light coming on for a a couple of times a week last year. It would go out after three or four re-starts. Then one day on the freeay the car just died!

Whenthe dealer looked at it he said that the O2 sensor was bad, so they replaced that. Then about three months later, about a month ago, the engine light started coming on again. So into the dealer (different dealer this time) it whent and he said that it not only was the O2 sensor bad but that the catalytic converter was not performing up to specs and had to be replaced. So I had to wait a week while someone swam over a new cat from Japan.

Has this happend to anyone else? A bad cat? Granted the bad O2 sensor would most likley lessen the life expectancy of a cat. I mean what causes TWO O2 sensors to go bad????

[Frank Hudon]

had two bad O2 sensors on my Tundra, LH sensor one and RH sensor 2 no cat problems though. It's entirely possible that the cat was defective from the get go. mean it's just made by a machine and as long as it passes inspection it's on to the production floor. Was it changed under warranty or did they try and stick you with the cost?

[Devil's Advocate]

I had purchased the extended warranty when I picked up the car last February which was good since I now have 36,000 miles on it. But they tell me the side benefit is I have rental coverage when I have a warranty repair.

So, No Toyota of Hollywood did not try and get me to pay and they got me a new Camry le (hate to say it but the car was kind of a pile, nowhere near the refinement of the Prius) rental to drive for the week that mine was out of commission.

I went to Toyota of Hollywood for a tire rotation and minor warranty check-up, and it just so happened that the check engine light was on at that time so I had them check it out, and viola, bad O2 and cat.

So all and all a good experience. I think a week was a long time to wait for the parts though and it cost me an extra $40 bucks in gas.

The real danger is that the car actually SHUT DOWN when the first O2 sensor went bad. Well the ICE shut down and the electric motor still worked, but that is only good for about two miles.

[Frank Hudon]

wife had a Chrysler Sebring and when the O2 sensor packed it in it would intermittently shut down to an idle and wouldn't accelerate. No CEL either and then about a week later the CEL comes on. Dang near got hit trying to cross a busy street when it did it.

[geologyrox]

Similar thing happened to my husband and a few years ago in his Celica. Check engine light intermittantly came on, would always go away again. Probably should have taken it in immediately, but it was fresh out of warranty... needed O2 sensor and catalytic converter replaced when all was said and done. Actually why we're getting the extended warranty - it gives me a few more miles per year to drive, and means I don't have to worry about stuff like this for 7 years instead of three. Glad to hear they got it fixed (if slowly) and gave you a decent rental car. Sorry you didn't like the Camry - glad your car is back on the road

[jayman]

I'm sure a handful of O2 sensors will fail early. As Frank mentioned, anything made will statistically follow certain failure modes. There is an entire branch of math devoted to this: FMECA (Failure Mode Effect and Criticality Analysis).

A bad O2 sensor can cause a motor to run too rich, and that will quickly overheat and ruin a catalytic converter. A tank of contaminated gas, especially with high levels of metal additives like MMT (Methylcyclopentadienyl Manganese Tricarbonyl) or tetraethyl lead, can quickly ruin an O2 sensor.

At one time, it was considered Preventative Maintenance to replace an O2 sensor every 50,000-70,000 miles. Not sure if that now applies, O2 sensors are way more expensive.

[Frank Hudon]

the heated O2 sensors on the Tundra were famous for not heating in the required time and the computer put the CEL on. There was a TSB on it but Toyota wouldn't change them once the initial warranty period was over. PMO because the second one failed 2800 Km past the end of the warranty period. That's when I found out about the TSB and took it to Toyota and they said to bad your past the warranty. Sent a letter to consumer and corporate affairs but no reply ever. Replace that one with an after market Bosch and shortly after sold the truck.

[jayman]

Originally posted by Frank Hudon@Jan 14 2006, 02:17 PM
PMO because the second one failed 2800 Km past the end of the warranty period. That's when I found out about the TSB and took it to Toyota and they said to bad your past the warranty. Sent a letter to consumer and corporate affairs but no reply ever.

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Frank:

Geez does that bite.

My 2000 GMC Sierra with Vortec 5.3 had 4 O2 sensors: one before each catalytic converter, and one downstream of the catalytic converter.

For giggles I asked the idiot GMC garage where I bought the damn thing from what it would cost to replace all 4: $940 dollars.

Jay

[Frank Hudon]

ya the Tundra had 4 as well 2 upstream and 2 down stream and they were $112 each. The Bosch was $87 and you changed the connector from the old Toyata sensor on to the wires on it and the Bosch worked fine. In the TSB it stated that the O2 sensor didn't heat (pre-heat) fast enough to satisify the computer. As most O2 sensors are heated types nowadays to get the system into trim faster things have gotten more expensive and complicated. No more $28 O2 sensors.

[jayman]

Toyota O2 sensors cheaper than GMC O2 sensors?

Hmmmm.