Hi guys, sorry if my question is stupid, but how many oxygen sensor does a MCS 06 has ?

Thanx.

 

2 - one before the catalytic converter (monitors oxygen content of exhaust to get the fuel to air ratio correct) and one after the catalytic converter (makes sure the catalytic converter is doing its job).

The one before the catalytic converter is the more important one in terms engine efficiency. Here's a diagram:

 

Thank you so much for your answer gknorr and both sensor are the same ?? or are different ?, to know when I have to replace it.

And the first one is the one that if is defective the car will consume more gasoline ?

 

They're the same sensors. As to when to replace - the check engine light will come on when they fail or do not produce adequate voltage. But, they do wear out over time and replacing aged ones before the CEL comes on could improve your gas mileage. Usually, they end up being replaced around 100k miles.

Yes, if the first one is defective, your car will get poor gas mileage b/c the computer will not know the proper fuel/air ratio.

 

Yes the precat one will cause bad gas mileage.
And they are the same sensors.But FYI,if you are planning to replace them I suggest you to replace the Pre cat with "Bosch 13878" and the Post Cat with "NTK/NGK 25648" ,It would save you some money.

 

Thanx so much for your advice guys, are more or less the cost of the pre cat sensor ?

When I bought my MCS 06 and my mechanic connect it to his scanner he noticed that the pre cat oxygen sensor was damaged/defective, I use very very little the car, only one day a week, so I never noticed yet any problem with the car to see some smoke or problems to start the car, so do u think I have to replace it ?? also I don´t know if the car is consuming fine the gasoline because I never have a MC, so I don´t know, but what do u think ??

 

Oops My bad...I meant Pre cat with the OEM NTK/NGK 25648 . And to replace it or not,its up to you,since theres light yet.You should measure the average MPG(pencil-paper method) to see how your car is doing.I replaced mine at 33,000 miles(yes thats crazy),it didnt throw any light but did show some codes,and the gas mileage was really terrible,about 17-18 for city and 25-26 for highway(i thought I had a V6 lol).

 

Hi again VipkohH,

What do u think about this one?

http://www.minicarparts.net/Parts/M3095.cfm

 

It would probably be okay for the post-cat sensor. I have an AC Delco replacement in the post-cat position right now that hasn't thrown any codes. However, when the very same AC Delco sensor was in the pre-cat position, I got the code for a bad sensor consistently.

For the pre-cat sensor, I recommend not wasting your time with anything else than the NTK/NGK 25648. You'll save yourself a lot of trouble! Here it is on Amazon:

http://www.amazon.com/NGK-25648-Oxyg...5454964&sr=8-1

Absolutely worth the extra $20 for the pre-cat sensor.

 

^+1

 

Thank you so much, for your comments. =)

 

Has anyone had issues with humidity changes having an effect on O2 sensors??

I have an 06 Cabrio S with 42k on it, and I get the SES light every time the humidity goes over 18% here in Vegas..... lasts a day then when humidity is gone, light goes out.....

Strange stuff. Just wondering if I should bother the stealership on having them replaced or not.....

 

Summit has the NTK 25648 for $130 each: http://www.summitracing.com/parts/NGK-25648/.

 

Anyone??

 

When my pre-cat sensor was on it's way out, I think temperature played a role on when I would get the SES light - the temperatures were usually in the 40's at that time of the year, but when it got to the 60's one day, the SES light came on. I replaced it before warmer temperatures came to stay.

I think your sensors would be replaced for free under warranty if it's obvious to the dealer they are faulty. I know they're covered until 100k miles - not sure how many years, but I think yours is still young enough.

 

Thanks....Temp doesnt affect it but humidity does..... I will check with the stealership

 

I was getting the code (forgot the number) indicating pre-cat sensor at fault. I ordered a single NTK 25648 from Amazon for $108 shipped. It was the last one in stock, otherwise I'd have bought two and replaced both. I figured this would be a quick 15-20 minute job, as I've had my entire exhaust (including manifold) out once, and know it's pretty clean under there. I was surprised at how tricky it was for me to break the pre-cat sensor loose. The O2 sensor socket I have is one of those low-profile ones that is a cross between a line (flare) wrench and a 3/8" drive crows foot. I couldn't use my long Snap On ratchet, and resorted to my 6" Craftsman 3/8" drive. Of course the connundrum there was little mechanical advantage. I wound up moving part of the front heat shield out of the way, and pried the end of the ratchet. Anyway, the job wound up taking about an hour. And I had to use my 1/4" drive torque wrench with an adapter going on. Mind you this is working on my back with the car on Rhino Ramps. I'm just a bit surprised since noone else mentioned this, and I keep reading how some people have trouble with the canister oil filter, etc. Are you all using the standard slotted deep sockets? I would think that would be even worse, but without trying, I can't say for sure. I also tried getting it from the top, but without moving the coolant reservior and tin, it was about the same story. Post cat looks like a 10 minute job tops. Of course now that it's done, and code gone, I'm having issues parting with another $108.00 just for posterities sake. Is the post cat an "if it ain't broke, don't fix it" thing, or should I consider it. For the record, the tank from right before the pre-cat switch netted 26mpg. Right after was 32mpg - both on 93 octane. I'll normally see 32 on 93, and 32 to 34 on 89 octane. 91 octane is tough to find around here. Oh, and my tailpipe isn't blackening as quickly :-P

 

I used a regular old 22mm wrench from under the car. The space was tight, but there was just enough working room.

As for your post-cat, if it's not throwing codes I wouldn't worry about replacing it. That one is just making sure the cat is doing it's job. I don't think replacing that one would help performance or mpg.

 

So is everyone unanimous that the Bosch ones will throw codes? if so I ordered the wrong ones from rockauto.com next to the bosch 13878 is says "OE type - Exact fit" and the NGK/NTK 25648 does not say that.

 

The Bosch ones certainly fit fine...and throw codes! NGK/NTK is the only way to go - I went through a headache of a time figuring it out!

 

I pulled the post cat one, wrote down the numbers and that is what I got at my NAPA dealer, which by the way was the NGK.

 

Newer mini cooper owner here, but wanted to share the "fix" on my 02 sensor and the problem that i had. I bought a 2006 Mini Cooper S Alta 15% SC pulley and Aftermarket exhaust system, little after I hit 50k miles and have a 02 senor "bank 1 sensor 2 Malfunction" my mechanic decided to put in a Bosch OE 02 sensor. Right from the the start my SNS light was flashing on and off 2 -3 times a week, after doing a little bit of research from North American Motoring looking through different forms I came up with he conclusion that it was a Combination of A.) the Ethanol additive that has been added to the gas after 2006 and also B.) that the "Bosch OE" Sensor doesn't meet the standards that Mini's ECU needs. 25648 NTK aka "NGK" worked the second I put it in and the sensor it self looked to be the same as factory o2 sensor no more on and off SNS. my word of advise stay away from the Bosch OE o2 sensor

 

Sorry you had to find out about the Bosch 02 unit the hard way, and that staying with the NGK Unit is the best, if not the only way to go, as others have been finding out for a while.
At least you ended up solving the problem and are back to Happy Motoring!

 

I used a 7/8 inch box end wrench after snipping the wires off the old sensor. I'm a pretty strong guy and I really had to muscle the old sensor to remove it. The NTK sensor was the exact match for what was on the car.

 

So i am now really confused, I thought i fixed my problem with my 02 sensor with the ntk oe replacement but I am now getting another "sns" light with a p0136 bank1 sensor 2 error. i am not sure what to do, my mechanic says i should put some cat cleaner in it but other than the front 02 sensor which sets up the second 02 sensor i don't have any idea what the problem is... any help