I could use some advice.

My Service Engine Soon light came on two nights ago while running up to highway speed on wide open throttle.

A local shop retrieved the error code: rear oxygen (O2) sensor

I have an appointment for next week at the dealer (long drive away), but I'd like to know what you all think.

Background: I have the v39 software installed. Runs fine.

I was in an accident and there was a fire under the car. They replaced a bunch of stuff, including the rear O2 sensor, and had to disconnect and reconnect the exhaust. This happened the day after I got my car back.

I have an aftermarket RSpeed exhuast and a Milltek header.

From what I've read on NAM, it could be simply a faulty O2 sensor. Could be bad wiring to it, but that was checked today and looked ok. Could be a bad DME, who knows what.

The garage in town and the dealer all suggested it could be the aftermarket exhaust, but I ran for 3 months before the accident without a problem. And my friend's identical setup works fine (except he doesn't have the Miltek header).

I actually have the 39.0 diagnostic sheet printout at work. I can dig up some kind of code if someone can point out to me where it might be.

Any ideas, suggestions, comments?

 

I'm looking at the V39.0 Diagnosis report regarding my Service Engine Soon light.

Test plan Start of diagnosis

DIS test plan

DME - P0136 Oxygen sensor (bank 1, behind cat.) - malfunction - no signal detected - Currently present (it goes on with more info...)

DME - P2270 Oxygen sensor signal stuck at lean (bank 1 sensor 2) - Short circuit to ground - Currently not present (...)

DME - P2270 (same as above)

DSC - 5E19 CAN data fault from DME/DDE (DSC lamp on as long as error is present) - Fault currently not present [not related, I suppose]

###

Anyone have any clues?

 

UPDATE:

I took my MINI to MINI of MURRAY in late December. They changed the rear O2 sensor, but they had me come back in early January for a re-check, knowing that it probably wouldn't fix it, but they had to try that first.

Left the dealership with the Service Engine Soon light off, but it came back on after a few drive cycles. Stays on for 10 more days.

Then I go back to the dealership on 3 Jan 2005, and they replace the two MAP sensors and clear the SES light. Sure enough, the light comes back on after just a couple drive cycles.

The SES light has been on continusouly since 3 Jan 2005 when I left the dealership.

Fast forward 17 days to this morning. I'm driving to work, and I notice that my Service Engine Soon light has turned off! It's been about 17 days since I left the dealer at MINI of Murray. The SES light has been on continuously since then and on for about 2 weeks before the 3rd of January, which was my last dealer visit.

17 days = 45 drive cycles? Probably.

Perhaps the issue *was* fixed during my last visit but took a large number of drive cycles before the light would go out on its own?

Obviously, I'll keep monitoring the situation to see if the light comes back on, but this is good news!!!

Any ideas or info anyone might have on why the SES light suddenly turned off on its own?

 

Sorry to reply on this post of yours i know its 2023 now but im having same issues. I can't get the p2270 fixed! Has the ses light came back afterwards? Do you have any idea how your ses light turned off? thanks.

 

First does the SES (service engine soon) light also serve as a CEL (check engine light)?

One must be able to read whatever code or codes associated with the SES or CEL.

Are you getting reading an active P2270 code?

P2270 points to a bad #2 (after the converter) sensor. Without benefit of the official MINI (BMW) diagnostics manual I would hazard a guess there are other tests/checks to perform to confirm it is the sensor and not wiring, connector, or even an exhaust system leak.

If you tell me the code is cleared and yet reappears shortly after engine start that suggests the problem has not been addressed by the replacement of the sensor.

If you have not cleared the code while you may (may) have addressed the source of the code it can take a number of warm up cycles before the engine controller will erase the code on its own and extinguish the SES.

 

Thanks for replying.
yes SES light and cel is same on my
R50 2002 mini Cooper. I change the catalytic, change O2 sensor post and pre-cat (ntk) cleared the codes and reset the ECM on the option on the dash, did the drive cycle but light came on after the drive cycle.p2270 & p0136 but the p0136 cleared after a few more driving but the p2270 stayed.

 

Thanks for replying.
yes SES light and cel is same on my
R50 2002 mini Cooper. I change the catalytic, change O2 sensor post and pre-cat (ntk) cleared the codes and reset the ECM on the option on the dash, did the drive cycle but light came on after the drive cycle.p2270 & p0136 but the p0136 cleared after a few more driving but the p2270 stayed.