Replaced both O2 sensors at 96,000 miles in anticipation of 100K maintenance spec, purchased from Atlantic British/MiniCarparts. Both looked good and went in fine, but "Check Engine Light" was on before and after installation. I assumed this was factory progammed interval for other service, so ignored it until 101K miles. Now, during service for defective airbag, dealer informs me that he cannot clear the light due to "aftermarket" O2 sensors, but he will gladly replace them with the "right" ones for $650. materials & labor. Call to Atlantic Mini Car Parts reveals that the sensors are in warranty, and they will ship new ones, and dealer will install for $180, but will not assure that this will fix the problem since these are "inferior O2 aftermarket sensors."

What should I do? I must get an inspection sticker within the next 25 days, and cannot do so until this problem is resolved. Is it worth removing the sensors, clean them and the connectors with choke cleaner and contact cleaner and then reinstalling them? I feel as if the dealer is employing thinly disguised extortion tactics to force me to use his parts and labor. Can there possibly be any significant difference between aftermarket O2 sensors and the OEM?

Clammy

 

What does Atlantic British/MiniCarparts have to say? Are the sensors made for the car?

 

Yes. According to them, these sensors are made specifically for the Mini, and they looked identical, but who knows about the internal electronic compatibility. The guy I talked to said he sells about 50 a month of these, and gets very few failures out of the box.

 

If I read your post right, you say the light was on before you installed the sensors? If that's the case, clear the codes and all will be fine. Any OBD-II scanner should be able to clear them. If they have been cleared and come back, then there's a problem still there. What codes show up?

Rawhyde

PS Sounds like the dealership extortion isn't even thinly disgusied.

 

Agree, you should clear the codes, if the light comes back on, what codes is it throwing? Recently I had the light come on and the suspect was the sensors but after having a smoke test, there was a vacuum leak at the by-pass valve. A simple new hose and no more problem...

 

To clarify, the dealer did clear the codes, and the codes returned following a test drive. I do not know what the codes were, but the dealer did tell me that first the front sensor sent a code, and then the rear and front sensors posted codes the next time. Is it possible that the sensors are sending proper voltages to the ECU but the system is unable to modify the air to fuel mixture as it should? My fear is that even after replacing the O2 sensors with Mini parts, the problem may persist, and the dealer will then claim that the problem is elsewhere, at additional cost.

 

Try to find out what the codes are and whether there are any symptoms (other than the light being on). I'd be glad to help if I can.

 

I purchased both O2 sensors from Minicarparts.net and immediately got an error code. They looked exactly like the stock Bosch sensors.

I replaced them with Bosch sensors from Advance Auto Parts and the error code stayed off when cleared, price was about $150.00/each.

I contacted Minicarparts.net and they issued me a full credit instead of a refund on return. You are the third person on this forum who has had problems with these sensors.

Good Luck.

 

Thanks for the feedback guys. I'll try to find out what codes the dealer found.

I'm thinking that I'll bite the bullet on this one and pay the dealer to straighten this out, and try to get a full refund from Mini Car Parts for a return of the sensors they sold me. I need to buy rotors and pads for the front brakes anyway, so a credit for sensors will cover about half the cost of the brake parts.

 

OK, here's the latest on this problem. I spoke to Mini Car Parts, and they sent me 2 new O2 sensors without any questions. Great guys to do business with, especially a guy named Brian Huebner. So today, I had a very reputable local garage (been in business since 1952 at the same place) with whom I have done business for years, install the 2 new sensors. Codes cleared, but when I picked it up the SES light came on. The tech. used his OBD to obtain the code "2097 - Post CAT - System Rich - Bank 1." The old timer who runs the place says that he's had all kinds of problems with aftermarket O2 sensors, and suggests I buy a genuine Mini sensor for the post-CAT position. What do you guys think?

Clammy

 

What is the freeze frame data reporting;what is the LTFT at idle and at 2500 rpm?

 

Sorry, but I have no idea what those readings are.

 

I understand, the freeze frame data is additional information that can be viewed from the OBD-II scan tool; but not all scan tools are capable of displaying this information. The OBD system is required to set freeze frame data for every code that is set; it is intended to aid the person troubleshooting the problem.

The LTFT is a parameter that can be displayed by the OBD-II scan tool. It stands for Long Term Fuel Trim; this value is expressed in percentage and generally should be in a range of +/-10%; outside of this range is an indication of a concern.

 

Thanks, Frenchie. I will try to obtain these readings for you, but the issue is to clear the code so I can get an inspection sticker. The engine runs just fine, but I suspect that the air/fuel mix is too rich and is dumping unburned fuel out the tailpipe. How to get the post-CAT O2 sensor to stop coding? So far the pre-CAT sensor has not issued any codes. I may just have to buy an honest-to-God Mini O2 sensor for $200.

 

Be advised that clearing the code to pass inspection does not work; the designers of OBD-II are ahead of you.

The car performs diagnostics on a number of pollution related sub-systems. These diagnostics test are refereed to as monitors; when you clear the codes you also clear the results of the test; what does this mean, you will fail inspection if the monitors have not run, even if you do not have a code set.

Starting in 2000 you are allowed to have one monitor not run. So if you choose to clear the codes you will have to perform a drive cycle to allow the monitors to run else the inspection station will turn you away. You will know the monitors ran if the scan tool indicates a yes in the readiness status