2006 Scion tC exhaust problems

[tjincville]

About 6 weeks ago at about 45K miles, the check engine light came on. The mechanic my company uses said the two O2 sensors were bad, so they replaced them a couple of weeks ago.

Since the replacement, my mileage has gone from an average of about 25 to 18 (about half freeway and half in town).

Yesterday the light came on again. Back to the mechanic, who offers 2 sequential things to do: 1) "flush" the exhaust system for about 5 and see what happens; and then 2) replace both converters for about ,600. (Aren't the converters under warranty until 60K among other things?)

I don't trust this mechanic much but the work is free to me. Does any of what they say make sense? Any help greatly appreciated.

[CadenceScion]

I would get a second opinion and from Toyota/TRD themselves, or take your tC back to where you bought it and have them look at the problem. I never heard of flushing the exhaust system, flushing the coolant system and transmission yes. If something smells fishy, 9 out 10 times it is. Mechanics are great when they are honest and not trying to make you shell out every last dime. Whom ever did the work prior may have cut corners and did a poor job, take the vehicle back and have them make it right at their cost not yours. You pay for work to be done right the first time, not after the second and third time.

[navylife59]

You are correct. I believe that it is Federal Law that emissions related components be covered for 60K miles. It maybe even longer. Cadence is steering you correct. Seek help from the Dealership. It sounds like your mechanic don't know squat as he is just throwing parts at the problem in an effort to troubleshoot. The MIL (Check Engine Light) disappeared because he reset it with his OBDII/CAN scan tool. It did not reappear due to trip logic nature of you DTC (error code). http://www.club-tc.com/forums/tc-kno...cause-mil.html

This will also help you to understand about the O2 Sensors. http://www.club-tc.com/forums/tc-kno...nsors-mil.html

Your MPG maybe going down either due to the malfunction or the mechanic's attempt at repair. In other words, he may have caused more problems. You need to have a serious talk with this individual about taking these parts back and reinstalling your old ones. FYI.... As a matter of course, you should always declare that you want any and all parts removed from your vehicle. They are your parts so they have to comply. Two reasons for this are to see if the part is actually getting replaced (being cheated) and if the new part does not resolve it, the old part is still good.

What are your DTC (codes) for the MIL? Do neither of the latter options. You would be throwing money down the drain. The "flush" for the exhaust might actually clog or damage your catalytic converters thus necessitating replacement of those cats. See where throwing parts on gets you?

[cmcpride]

are you still having problems with your tc