I have a Miltek exhaust system and get a frequent SES light. The code is for O2 sensor. These have been checked, and even replaced, but the code still shows. My mechanic says he's heard that aftermarket exhausts will sometimes cause this false reading. (In general, not specific to MINIs)Anyone else had this problem or heard that aftermarket exhausts can do this? Or is this just a MINI problem re: false readout for O2 sensors?

If this is the problem, is there a solution?

 

When i had my cat welded on to my header at a local shop, my ses light came on. When i looked under the car, i realized that they plugged in the sensor then tightened it. If you plug it in first all the wires will twist. This caused one of the wires to have a small rip in it which tripped the light. That could be it.

 

You don't have to touch the O2 sensor while installing the catback, so it shouldn't be the case.

Curiously, the same thing happened to me when I only had the Milltek with the OEM header, but very rarely. It would happen once every month or so when leaving from work, specifically before the car reached operating temps. It would go away after a couple of days.

I have not had the problem since installing a header with the OEM cat welded on, go figure...

 

if its a major issue....get an o2 sim...it just keeps the o2 sensor for the cat happy and your cat will continue to do its job....or maybe...just maybe...your cat is in fact starting to fail and the o2 sensor is working...one way to test your cat is to measure the temps before and after the cat with an infared gun. They will be the same temps until the cat goes into lite-off, then you will see a 100 degree F higher temp difference after the cat. You will only see this when the car is cold. If the car is hot and the cat is already up to temp you will just see the 100 degree difference pre to post as the cat will be already lite.

 

I am just about to post a for sale thread in the marketplace for a brand new o2 sim if you anyone is interested...

 

if its a major issue....get an o2 sim...it just keeps the o2 sensor for the cat happy and your cat will continue to do its job....or maybe...just maybe...your cat is in fact starting to fail and the o2 sensor is working...one way to test your cat is to measure the temps before and after the cat with an infared gun. They will be the same temps until the cat goes into lite-off, then you will see a 100 degree F higher temp difference after the cat. You will only see this when the car is cold. If the car is hot and the cat is already up to temp you will just see the 100 degree difference pre to post as the cat will be already lite.

 

damn, your right

 

I have had my SES light on for about a year now and have not been able to have it turned off no matter what I've done and how many shops have looked at it 2 of which have been 2 different Dinan shops.

My codes show 2 different vacuum leak from the tank: p0422 and p0456.

Dinan has done a smoke test 3 times and can't find any leak and are now puzzled about the whole SES/codes thing. They want to start digging in and take parts off one by one and test the car to see where the problem is. I have declined to take that rout of course and still have the darn SES light on.

Good luck with the problem, I hope you find it and take care of it. I have not been so lucky and don't think I will be anytime soon. I am just driving the car now after having the car spend 2 months in shops trying to figure out how to fix the SES light.

 

[quote=SharoSC02;2202929]I have had my SES light on for about a year now and have not been able to have it turned off no matter what I've done and how many shops have looked at it 2 of which have been 2 different Dinan shops.

My codes show 2 different vacuum leak from the tank: p0422 and p0456.

Dinan has done a smoke test 3 times and can't find any leak and are now puzzled about the whole SES/codes thing. They want to start digging in and take parts off one by one and test the car to see where the problem is. I have declined to take that rout of course and still have the darn SES light on.

Good luck with the problem, I hope you find it and take care of it. I have not been so lucky and don't think I will be anytime soon. I am just driving the car now after having the car spend 2 months in shops trying to figure out how to fix the SES light. [/quot
I don't know if this will help put i had a vacuum code come up and said that the tank was leaking or something like that. I've found out the the vacuum line on the master cylinder was crunched a bit and made the ses light come on. Once i straigtened it out, the light turned off. It also affected my braking my making the peddle harder than what it should be. Just thought i'd throw that out.

 

[quote=grillhands;2203014]Do you have a visual as to where this line is. Can you provide/take a picture of it or is it too hard to get one and post here so I can use as a reference?

Thank you in advance.

 

I have an 03 mini cooper s and i just put a full system exhaust on, and my ses light came on. I hooked it up on a scaner on it told me it was my cat senser.. There is no cat on it there is just a resignator. What can i do to get my light to stay off??