Code came back today, but I think its just because the rear sensor which I moved to the pre-cat position is on its way out (as one certainly might expect). Interestingly, it also managed to throw a P0304 code (4th cylinder misfire). Probably just a bad reading from the O2 sensor that caused it.

Temperatures turned a little colder later in the day, and the code disappeared. Same sort of behavior was happening when the previous pre-cat O2 sensor started to go: fine when outside temps were cold, but would throw the code when warmer outside.

Ordered a Bosch replacement today from Amazon and am fairly confident that'll do the trick.

 

Umm...apparently the Bosch is not the exact replacement, despite my confidence above. In fact, it may have problems of its own - note the post by "Chadtoolio" here:

https://www.northamericanmotoring.co...r-problem.html

When installing the new Bosch one today, the tip was defintely different. The original sensor which I pulled was marked as a "NKT 0872674/L-FLO" So the originals may in fact be NTK and not Bosch. And...my SES came back on with the new Bosch in (it had been off a few days with post-cat sensor now in the pre-cat position)

As much as I've been trying to avoid it, I think I may just give in to buying the super expensive sensor from the dealer. I'm just getting tired of trying all these sensors and still having the light on. And, in my case, I know its the sensor because when I put the old post-cat one in the pre-cat position, SES goes away...until it gets warm out.

What's hard for me to believe is that the car would be so incredibly sensitive to the brand of O2 sensor you put in. But, it seems to be the case...

 

It's not a matter of the sensitivity of the ECU. It's a matter of proper resistance. Changes in your air-fuel ratio register as a varying voltage. If the expected value is incorrect, the ECU will give an SES and indicate the O2 sensor is bad.

...


Some additional O2 sensor threads:

https://www.northamericanmotoring.co...r-install.html
https://www.northamericanmotoring.co...placement.html

...

Yes, the Bosch is not worth it. I previously noted the AC Delco equivalent as an alternative, but I am not sure if it does in fact work correctly, either.

http://www.oehq.com/acdelco-parts_21...20S%201.6L.htm

...

OEM part number is 11 78 0 872 674. KO Performance has the OEM NTK sensor for $165.84: http://www.koperformance.com/online_...1780872674-209.

 

The first pre-cat replacement I used was an AC Delco. SES would intermittently go on and off for the first few months I had it in. After those first few months, SES just stayed on. However, the AC Delco hasn't thrown any codes in the post-cat position...yet.

What about this NTK replacement?
http://www.amazon.com/NGK-25648-Oxyg...0193528&sr=8-1

Since it doesn't have the same markings as the original from the car, I called the guys at NTK to ask if they are the exact same sensors as the MINI OE sensors. He assured me they are and should work identically. I may give yet another sensor a try...hesitantly.

 

Finally! I can now confirm that the NTK 25648 O2 sensor is an exact replacement for the MINI OE ones. In addition to NTK assuring me it is the identical sensor, after having nagging P0130 codes for half a year and trying both the ACDelco and Bosch sensors to no avail, I put the NTK in and haven't had a problem at all.

I found out the originals are NTK when I pulled the old one out. Was clearly marked with "NTK," but had to call NTK to make sure #25648 would be the same as the original MINI sensor, since the numbers didn't line up. Apparently the reason for this is their aftermarket parts have a different numbering/cataloging scheme from OE MINI, even though the actual sensor is identical.

 

I too replaced both O2 sensors with Bosch universal. I started getting P0130 code within days. I reset and every couple days later the code comes back.
I put a AutoEnginuity data logger on the OBD-II port and watch the O2 sensor seeming perform correctly.

After reading this thread I suppose I need to order NTK sensors.

 

That's what I would try - the NTK I put in a while back is still going strong. You should be able to get your money back for the Bosch ones though - I got mine from AutoZone and told them it didn't work for Minis and got a full refund.

 

It seems the P0130 code only gets set when the car is cold.
3 or 4 warm starts and the code clears.

Is that a heater problem?
I ohmed the white leads before installing the new sensor and there was resistance.
Perhaps not the right amount for what MINI computer is expecting.

 

Hmmm...when my original sensors were on their way out, just the opposite was happening - code triggered when warm outside - cold starts fine.

If you haven't switched to NTK's yet, I would try that before searching for other possible issues. I started thinking I might have an exhaust leak, but it really was just the sensor brand the entire time!

 

A couple of years ago I had the classic p0130 problem. I replaced the sensor with a Bosch (bought on-line) and when the problem didn’t go away I bought one from the dealership. Still no dice. I took my little Mini to the local Palo Alto Bimmer shop and had them look at it. They put in a new O2 sensor (yes, that’s the third in less than a month). It worked for a week then threw the p0130 code again. Back to the Bimmer place it goes, they do some magic for free and I’m fine. Great, all fixed.

Fast forward two months ago. I take the Mini to get smogged and it throws a light while on the dyno, p0130 AGAIN. I’m like wtf? After a bit of messing around I finally take the car back to the PA Bimmer place. I explain what’s up and that it’s NOT the O2 sensor (but what do I know right?). They put in 2 (that’s two!) O2 sensors and tell me that it’s not the O2 sensor—and then charge me for it. They proceed to tell me it’s the computer, “everything else checks out”. So here I am with a persistent O2 sensor problem that the “pros” can’t fix. Must be a computer problem.

On the web I go to find a new computer for something less than $2000 and $250 for installation (plug in two wires). After a chat with a nice guy at RPM motorsport he talks me into NOT buying a rebuilt computer for $700 but rather opt for an unlocked one (read, it won’t check the key antenna for security but do I really care?) for $1100 instead which is returnable for a 30% restocking fee. Computer comes, car still throws the code and long story short it was NOT a computer problem. That cost me $350 but that was better than $700 or over $2200 from the “pros”.

So what was the problem you ask? Well, I’m not 100% sure but the car is now fixed. Pickup is back to normal, no bogging down and not a code for weeks, RPM motorsports has refunded 70% of my money as promised, and the old computer is humming along just fine. Here’s what I ended up doing—I swapped the O2 sensors, cleaned them off and drove the car a LOT, I drove the car for about 250 miles at highway speeds. I don’t drive my car very much (I bike to work) and typically only go a few miles in it. I noticed during my long drives, “to reset things for the new computer”, that the engine temp went up fairly quickly but OIL temp takes a good 20 minutes of highway driving to reach operating temperature. During most of my driving my oil temp NEVER gets up to normal operating temperature, in fact it hardly moves at all. So I’m going to go out on a limb and say that driving/cleaning/swapping is at least part of the cure with the driving being a top bet in the car’s cure. So if you’ve got a persistent O2 sensor problem try cleaning them off a bit and then drive, Drive, DRIVE. You've got nothing to lose but a few gallons of gas. I recommend something other than loops around 101 and 280; but it works in a pinch.

 

Get rid of the Bosch O2 sensors. They don't provide the right resistance, and the ECU will continue to throw codes. The OEM replacement is the NTK 25648. I just replaced both of mine at my 100K maintenance window on my '06 MCS. No issues whatsoever.

The Pros are probably insist on using the Bosch sensors. And one would think that's the right thing because it's a German company. But they just flat out don't work.

 

Ahhh, yes. JJF has a point, best to use the OEM stuff when things are a bit funky. And anything involving the car computer is probably a bit funky.

I wasn't too clear about my sensors with regards to brand. The one Bosch I put in was the only non OEM one. So all told that one slot (pre-cat) has had 6 O2 sensors since I purchased the car (used), 1 Bosch and 5 OEM. Replacing the sensor never fixed the code. I sure wish there was a good explanation to what goes on with the 130 code but I have to admit I don't know of one.

Just one of these days I'd like to get a fault code that doesn't send me on a wild goose chase. Oh well, now to figure out why my rag top doesn't always snap into place on the drivers side--back to the forums!

 

Update. About 3 weeks ago the same P0130 code came back. Swapped the pre and post cat sensors and no dice. This time I took it to the dealer. I gave them a full page of data on how many sensors it's had, the computer replacement etc. Long story short they swear it's the O2 sensors and after two new OEM sensors and $1100 they say it's good to go. 40 miles later the engine light is back on. Now my car has had 8 (yes, that's eight) O2 sensors. My conclusion is that every BMW/Mini certified tech I've taken it to is 1) only certified in how to read through a cheat sheet and 2) has no idea how to fix a car if it's not on the cheat sheet and 3) thinks that a customer that has done 90% of his own automotive work for the past 35 years is stupid. So back to the dealer I go. This time I asked them how much for my car and took the $5500. Now they'll get to fix it for free when the next buyer brings it back in. I really should have sold it to them before spending the $1100 and putting in the new clutch for $1600; some lessons are hard to learn. Now to unload the scanner and manuals. Sigh!

 

Something does not sound right. Maybe the catalytic converter was bad?

 

I just purchased a 2004 mini cooper S, has the PO130 code. Since the o2 sensors were most likely original I bought two Bosch plug and play o2 sensors the code will come on sometimes a minute after start up but I drove 100kms after erasing the code and never came on...

I dont beleive that the issue can be the Bosch sensors because there not OEM. There new and should provide an accurate reading. I am leading more toward vacume or manifold leak.... any advise?

Marc.

 

I'm almost certain your issue is the bosch sensors - I experienced the same thing a few years ago. The engine management system is very particular on MINIs and you need to get the NTK sensor for the pre-cat position (NTK is the OEM brand). The post-cat sensor is a little less particular and you might be able to get away with leaving the Bosch there.

NGK 25648:

 

Thanks for your input! I have also read other sources having issues with the bosch O2 in the pre cat position.
I will try my original post cat sensor in the pre cat position, if that works I will order a new NTK O2 sensor.

 

The code is gone! Just passed the E-test this morning, thanks guys!

I will order a new NTK O2 when this one is done and keep the Bosch O2 in the post cat position.

 

There's a lot of information about O2 sensors and how individuals faced similar issues with the Bosch sensors in this NAM thread here. Recommendation was to make sure to use the NTK O2 sensor for the pre-cat sensor so that you don't have an issue with codes being thrown.

We also have more info on the replacement and using an OEM sensor for the pre-cat here: http://www.pelicanparts.com/techarti...eplacement.htm.