Grr. Someone clipped the front driver's side corner of our car today. It was parked on the street near the elementary school and they were pulling in front of it to park. It looks like we'll need a small dent hammered out of the fender, a new light housing, and a new front bumper.

Fortuneately, they left a note on the windshield. It's even someone we know.

And the really good news is that we need to get it inspected this month, and Mrs. Glatt had just inspected it a couple hours earlier. So there won't be a rush to get it fixed AND inspected before the end of the month.

Fuckin Christ

Yeah, assuming that it really truly is a failing emissions level triggering the light, and not a poor gas mixture like Lamplighter suggested. If it's a gas mixture problem, turning off the light may allow it to stay off, or it may come back on again and then I'll know for sure.

Mr. Clod and I were calculating, how many "expired inspection" tickets I would have to be pulled over for before it became worth the cost of a new catalytic converter... it's a lot of tickets.

Just pulling stuff out of my ear here but ...
The fact that both LH and RH (left hand and right hand?) catalysts are showing errors at the same time suggests either:
a. These catalysts are shitty and have a poor lifespan built in or
b. The catalysts are fine and the problem is caused by some factor shared between them, most likely the gas you are using.

B. Let it be b.

ETA: or c. the catalysts were fine but have been irreversibly cocked up by using shitty gas. Hope not.

You've got the cats, and some sensors (usually oxygen sensors) to report back to the computers how the cats are performing. A bad report could be a failure of either.

Only after you're sure of what the problem actually is, then explore your options
Here's a couple out of a list of 76.

The combination of codes imply a least expensive suspect. To say more requires information you cannot obtain.

Appreciate what you have and what is relevant. Oxygen sensors do nothing until the engine heats them to maybe 600 degrees. During a warm up period, the engine dumps larger amounts of gasoline into the engine. Much unburned gas is then burned by the catalytic converter when it gets hot.

Once the oxygen sensors get warm, then the engine computer changes a fuel input. Leans out the mixture based, in part, on data from an oxygen sensor.

Apparently you have two sensors. If one is proving bad data, then the engine will dump improper amounts of fuel into the engine. This can result either in a too lean mixture (causing exhaust valve failure) or too rich (causing catalytic converter failure).

A most likely suspect is a bad oxygen sensor. Fix it now to avert damage that may cost $thousands.

Bad gasoline causing this problem would be noted by mileage changes approaching maybe ten percent. Of the maybe 100 other possible errors associate with the converter, gasoline might only explain less than ten.

This failure could be something as simple as an oxygen sensor with a failed heater. Then the engine computer, after a delay, would be expecting data that was incorrect. Or it could be a thermal junction failure inside that sensor. Either way, a $100+ sensor is a least expensive solution. I believe you have two. Don't know if the shop will want to replace both or just one.

Again, your reply is only as useful as facts first provided. You (typically) cannot obtain numbers necessary for a better answer. The shop can.

But in that case, wouldn't the presence of both (LH) and (RH) codes mean that both oxygen sensors had to fail at almost exactly the same time?

Your cats are covered by a 8 yr /128,000 km waranty, has that expired?

Yeah, it was eight years old this past January, and has almost twice that mileage. But I've decided I can afford the diagnostic, and if they tell me I need new catalytic converters, I'll just tell them no and start figuring out how to wreck the thing for an insurance payout. ;)

i talked with a friend of mine about this. we came to the same conclusion. if the "good" gas doesn't solve your problem, replace both of the o2 sensors at the cat first. then if you still get the codes, you have a bad cat.

BAAAAD KITTY !!!!

Might be something here http://www.ifixit.com/Browse/Vehicle

If you need new converters, then an engine defect caused premature converter failure.

I mentioned two oxygen sensors. One before the converter and one after. Many cars do not use a sensor after the converter. But all must have the sensor before. Why would an engine problem cause its computer to detect those errors? A first sensor is giving bad numbers. Engine responds with a bad fuel to air ratio. Then a sensor after the converter reads bad numbers.

You don't know what to replace. This is just one likely suggestion. A likely suspect is one oxygen sensor causing bad numbers or improper engine operation. I see no reason to jump to a bad catalytic converter conclusion. Follow the evidence before fixing anything. The above scenario describes one possible reason for those codes.

Is the evidence a trail of money? Because I could follow that, and then fix anything.