oxygen sensor replacement on 2001 Sienna?

[loshjott]

The "check engine" light came on in my 2001 Sienna. I brought it in to the garage, the mechanic did diagnostics and said one of the oxygen sensors needs replacing. He quoted a price of $425. He said it is drivable until replaced, but that the sensor would need replacing to pass the emission test. I live in Maryland. Does this sound accurate and legit? Thanks.

[vicchang]

Hi, my 2000 Sienna had the same problem couple weeks ago. I called couple Toyota dealers for quotes. They want charge from $400 - $550. So the price you got is not too off. But if you want to avoid the expensive labor, one of my friends has a private garage in College Park area. He replaced the sensor for me for $320 parts and labor (genuine Toyota parts). I think that's a pretty fair deal. So, maybe he can help you on this if you are not too far away from his garage. Let me know.

Victoria

[sreisiger]

My check engine came on as well and I failed the emission test with a P0171 and P0174 "running too lean" - The problem was with the Mass Airflow Sensor (MAF). It sits between the air filter and the throttle body. I took it out (2 screws and a clip) and the inside of the tube looked somewhat dirty. Sprayed carb cleaner in there a couple times and plugged it back in. Seems to have done the trick. A new one is about 75 bucks. Van no longer has a buzzing sound on acceleration. I thought this was the exaust heat sheilds but in actuality the engine was knocking due to the improper fuel/air mixture because of the dirty MAF.

[mikhett]

in a 1/2 hour.On a 01 v-6 the front one is right there behind the radiator,You must have a 7/8 o2 socket,Just unclip the electrical connector and replace. Part cost 185.00

[Dr Know]

Thanks, Sreisiger! I had the same problem in 2008 on my 2001 Sienna, two codes, P0171 and P0174 I think, both reporting "too lean" mixture, plus occasional engine hesitation. Not believing a local mechanic's guess that two sensors could fail simultaneously, I searched for a common root problem.

After seeing what you wrote, plus similar thoughtful discussion on http://www.aa1car.com/library/ford_lean_codes.htm, I agreed with trying the cheapest solution first: I gently removed the mass air flow with a Philips screwdriver, sprayed the heck out of it with a half-can of "CRC MAF sensor cleaner", put it back, and reset the engine check light by pulling the EFI fuse for a minute. The check light stayed off, and all has been well ever since for over a year ... almost.

Only other problem was an air-fuel ratio sensor that actually did fail some months later. Perhaps just old age, unless I caused it by driving with a bad mixture a little too long.