Need Some Help with Odd O2 sensor issues

slowbrick · 07-13-2020, 08:14 AM

Background info

Car is fully deleted with a tune. Im not going to put names out there as the place has done 3 tunes for me now with zero issues and this may not be related to the tune. However after getting the DDE back this time this issue has been ongoing for a month.

When I first received the DDE back, the SES came on for egt sensor(pre-cat) and O2 plausibility. I deleted the codes and no SES light for about 250 miles or so which for me is about a week of driving. This issue repeated for about 4 weeks before I started getting a different code when the light came on. The new message is "O2 sensor out of range during deceleration". See below the first image.

So after checking all the electrical connections for the O2 sensor and EGT sensor and finding nothing frayed, split, disconnected etc... I bought a new OEM O2 sensor since my friend gets them at cost. I installed it over the weekends and cleared the codes. Same issue. Ive gone in and reset all adaptions with ISTA for MAF, MAP, etc. Same issue. See images 2,3,4.

After reading some of the functional description info in ISTA, it says to reset the MAF which has been done several times correctly or check for exhaust system leaks. Could an exhaust leak be the culprit? I'm going to check from the turbo back til the tail pipes on Tues but I want some others input on what else may be causing this.

The car runs as expected when the SES light is off. All values for AFR etc seem to be where they need to be. When the SES comes on obviously the emergency fuel tables kick in and it runs rich killing my mpg. I'd really like to get this resolved asap obviously but Im kinda scratching my head of where to go next. Any help is appreciated or we can collectively brainstorm.

slowbrick · 07-17-2020, 11:11 AM

After further inspection, leaning towards a leaking exhaust gasket. Any one else have any input?

IssaSaiwak · 07-19-2020, 02:41 AM

having the same issue. any updates?

slowbrick · 07-21-2020, 11:53 AM

Yes I solved mine. Tightened Vband clamp on the downpipe better and made sure all the turbo crossover piping was properly seated. 250 miles later no issues.

07-13-2020, 08:14 AM	#1
slowbrick Private First Class 48 Rep 102 Posts Drives: 2017 M2, 2003 M3 Join Date: Sep 2016 Location: Florida iTrader: (2)	Need Some Help with Odd O2 sensor issues Background info Car is fully deleted with a tune. Im not going to put names out there as the place has done 3 tunes for me now with zero issues and this may not be related to the tune. However after getting the DDE back this time this issue has been ongoing for a month. When I first received the DDE back, the SES came on for egt sensor(pre-cat) and O2 plausibility. I deleted the codes and no SES light for about 250 miles or so which for me is about a week of driving. This issue repeated for about 4 weeks before I started getting a different code when the light came on. The new message is "O2 sensor out of range during deceleration". See below the first image. So after checking all the electrical connections for the O2 sensor and EGT sensor and finding nothing frayed, split, disconnected etc... I bought a new OEM O2 sensor since my friend gets them at cost. I installed it over the weekends and cleared the codes. Same issue. Ive gone in and reset all adaptions with ISTA for MAF, MAP, etc. Same issue. See images 2,3,4. After reading some of the functional description info in ISTA, it says to reset the MAF which has been done several times correctly or check for exhaust system leaks. Could an exhaust leak be the culprit? I'm going to check from the turbo back til the tail pipes on Tues but I want some others input on what else may be causing this. The car runs as expected when the SES light is off. All values for AFR etc seem to be where they need to be. When the SES comes on obviously the emergency fuel tables kick in and it runs rich killing my mpg. I'd really like to get this resolved asap obviously but Im kinda scratching my head of where to go next. Any help is appreciated or we can collectively brainstorm. Attached Images
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07-17-2020, 11:11 AM	#2
slowbrick Private First Class 48 Rep 102 Posts Drives: 2017 M2, 2003 M3 Join Date: Sep 2016 Location: Florida iTrader: (2)	After further inspection, leaning towards a leaking exhaust gasket. Any one else have any input?
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07-19-2020, 02:41 AM	#3
IssaSaiwak New Member 2 Rep 5 Posts Drives: 2010 Bmw x6m Join Date: Sep 2019 Location: St Lucia iTrader: (0)	having the same issue. any updates?
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07-21-2020, 11:53 AM	#4
slowbrick Private First Class 48 Rep 102 Posts Drives: 2017 M2, 2003 M3 Join Date: Sep 2016 Location: Florida iTrader: (2)	Yes I solved mine. Tightened Vband clamp on the downpipe better and made sure all the turbo crossover piping was properly seated. 250 miles later no issues.
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