In reply to iceracer:
Technically, the sensor does not measure voltage, it generates voltage- and that voltatge is directly related to the partial pressure of O2 on either side of the sensor. It acts as a battery.
Smaller point....
(although, I think the point he was actually making is if the sensor is a basic 4 wire NB sensor or a 5/6 wire WB sensor)
Around here, O2 sensors on 10 year old cars are NOT 5 minute jobs. Ever.
I couldn't afford to own a car if I couldn't fix it myself. The chances of me getting rich by the time I'm unable to fix my own car is slim to none. I hope my son makes it so he can support getting my cars fixed for me when I can't do it myself.
To me that's crazy expensive. But mechanics make a lot more money than I do.
While I think Midas sucks...
ebonyandivory wrote: Dads 2004 Camry 2.4L failed inspection for emissions for an O2 sensor at Midas. He shows me the bill to replace it: $82.41 just to scan it while our locals parts stores all do it FREE.
Scan or diagnose? Scan tells you what code there is. Diagnose tells you what the problem is. Auto parts stores will tell you what there is for free because they want to sell you parts, and they don't care that (for example) that front O2 code is caused by a blown DRL fuse.
Parts total (one o2 sensor) $205.49
Probably a wideband. (edit: or not, see below)
Labor total $204.80
Seems a little steep, but it could have been a big fight to remove. The only times I've had to remove them on the 2.4 were in replacing a failed cat, and we try to sell new upstream and downstream O2s with new cats, so I don't remember ever actually trying to remove one...
I can get an o2 sensor for under $30 and maybe if I'm slow, take a half-hour to replace it.
You're really not going to find one for $30.
List for a rear O2 for that car for me is $235. List for a front O2 for me is $385. That's the part on the shelf, no diagnosis or fighting a bunch of corrosion on a ten year old car...
In reply to Knurled:
shame on you for bringing in reality to this. 
It sounds a little salty, but not obscene to me, considering the situation.
I did have a shop try to screw me on the downstream o2 on SWMBO's Cherokee.
They were putting a new exhaust on it after the meth heads destroyed her OEM one. Shop tore the threads off the sensor removing the sensor from the old exhaust. No big deal, it was 13 years old. They called me and said they would fix it, but would be tacking on another $350 to the bill for it for "parts, labor, and diagnosis." Oh, and that they couldn't just not repair it, because it was an emissions issue.
I nipped that E36 M3 in the bud real quick. I simply asked "what sort of a downstream narrowband o2 sensor costs that kind of money?"
"Well... it's an OEM Bosch, and we charge 10% markup on prices because we have to go get it. $50 for diagnosis, and figure $50 to install it."
"....That's funny. OEM part is an NTK sensor, which is available for $60 at any parts store close to you. I'm also not paying you a diagnosis charge, since the diagnosis is 'threads are gone from when we removed it. Leave the plug in the rear cat, i'll replace the sensor in your parking lot before i leave so you don't have to report me for emissions violation or whatever."
"Well.... i guess we can do that."
$25 and 5 minutes later on my back in freezing rain, we were on our way.
I'm kinda over this, he did what he did and although I'm not happy with the bill let alone the decision to go to Midas, it's over and won't happen again.
I'll just add that the sensors I've searched from Partsgeek etc run from $65 to $135. Sure I can find the odd $190 one, they're way cheaper than Knurled found.
I reiterate: I've done about five domestic and foreign o2 codes and fixed them all with a ~$40 sensor. So take that for what it's worth.
I appreciate all who contributed. Of course most of it was not what I wanted to hear but I'd rather get the truth than get coddled truth be told.
For what its worth, you're taking this quite well.
Also for what it's worth, I just grabbed OE-grade parts from our main supplier. If we were putting together an estimate, you can be damned sure we'd try to find something less "No, really, it's how much?"
At the same time, though, there is no economy in cheap parts. If you have to do it twice, you've just thrown away any money you made on the job, as well as pissing off a (possibly former) customer who now thinks you couldn't repair your way out of a paper bag.
Bosch "universal" O2s are almost always junk, FWIW. One wire and heated. Have seen this for maybe five years now. I had a friend whose Audi (think CIS-E) was running like poo, horrible fuel economy. He insisted that the O2 was good because "it was new". When he told me that it was a Bosch unit, I insisted that we get that POS out and put something that works in the car. I happened to have an NTK 3-wire in my car ($5 scratch-and-dent score from Summit, OE app was... something Nissan) and we wired it in and sure enough, the O2 would actually wake up and put the computer into fuel control...
"But it was a BOSCH!"
Yeah, and that sadly means diddly-squat for aftermarket O2s.
alfadriver wrote: In reply to iceracer: Technically, the sensor does not measure voltage, it generates voltage- and that voltatge is directly related to the partial pressure of O2 on either side of the sensor. It acts as a battery. Smaller point.... (although, I think the point he was actually making is if the sensor is a basic 4 wire NB sensor or a 5/6 wire WB sensor)
Not a battery, doesn't store anything.
Create/generate ?
Pressure of O2 ?
A narrow band oxygen sensor creates a small voltage based upon the quantity of oxygen in the exhaust. An air/fuel ratio sensor, or wide band sensor as they are known in the enthusiast world, measure the current flow through the sensor, not the voltage. The voltage is supplied and kept stable by the ECU.
http://www.aa1car.com/library/wraf.htm
Actually, the air/fuel ratio sensors don't generate a current, the computer sends a current through them to alter the switching point. They are still kinda-sorta narrowband sensors, but the electron pump thingus can be varied by external control, and the amount of control required to make it switch is how you determine what the air/fuel ratio is. This is why you can thread a narrowband O2 into an exhaust system and read it with a voltmeter, but a wideband requires a controller unit.
Now, what I want to know, is how Toyota managed to condense everything down to four wires for their "air/fuel ratio sensor".
This is also, BTW, why Toyota stuff can be so hideously expensive. 90% of the stuff on the market is Bosch or NTK as far as O2 sensors go. Toyota had to do things their own way. Which is why you pay through the nose for a Toyota sensor, while the Bosch 7-wire unit is $35 from Autozone. The NTK is more expensive, but less than Toyota. (IIRC it can be had for as little as $100)
Heck, even the narrowbands. Everyone else in the world uses a 16x1.5 thread O2 sensor, Toyota had to do the goofy flanged O2. Why? Because screw you, we're doing it different.
In reply to Knurled:
You make a good point. I tore my remaining hair out trying to fix my non-running Tiburon. I shade-tree diagnosed it as a bad fuel pump so off to Autozone I go for a new one. Installed it in about a 1/2 hour. Still wouldn't start so I dug into the timing, cam-position sensor, whatever I could think of that it could be.
Turns out after months of it sitting and me frustrated, the shop I took it to (mentioned by name earlier in this thread) diagnosed a.... You guessed it, bad fuel pump.
New, in the box straight off a Sampan it was junk.
Important Fact alert: the two-bay shop I took/take my car to didn't charge me a penny to diagnose my car and I ended up selling it to someone they hooked me up with!
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