O2 sensor failing? Increased emissions, Engine malfunction

[///Monty]

Do you have a moon roof and has it been raining? There is a sump drain that goes to the rear of the car through there, just like they go through the front to the front quarterpanels.

[strokemycocktus]

Gary, I'll check these black things and use them to drain the water. I am not sure if I would get a pool full of water if the drain pieces were faulty though.
///Monty, no sunroof on my car.
I'll put a ton of paper towels everywhere and maybe we can figure out something more after it gets wet again.

In the meantime, I plan to determine whether my battery is fine. I think I'll check the voltage through OBD with ignition on/engine off and then with engine on on idle - if these are low I'll take the battery to charge for a night and check it again after a few days - does that make sense? What values should I see with a good battery?

[M3 Number 86]

dang - i feel for you. in my experience, one fault will consistently trigger a ton of other faults since they're all connected somehow. It could be something simple and cheap or not. For example, i had a small leak at the header to xpipe joint and it was throwing all kinds of o2 sensor, fuel sensor, lean code, all 8 cylinders, limp mode...i replaced a few different things and low and behold it was a stupid leak lol

I recommended looking at o2 sensor live data since that is free. Do you have one of those cheap obd 2 readers? I bought mine off amazon for $30 and it shows live data that I need. so just want to make sure that those systems are good before moving onto the more expensive parts. you can try swapping out o2 side to side but know that can be a hassle and hence the looking at live data.

just did a quick search and battery should be 12.3 or above. if you notice things like comfort access not working accurately or your angel eyes no longer turning on when you lock/unlock, those are tell tail signs where you might think otherwise.

check these things if you can and if those are ok, it may be throttle actuators just because the codes are there. i don't think i've ever seen TA codes when it was TA. my car would intermittently go into limp mode for a few days when TA was failing. something along the lines of - since the gears erode and skip, the car starts reading as if they were normal and skipped, then throwing codes/limp. I don't know what the cheapest way to test this would be besides just removing them and having a look inside.

I went with mpower motorsports and replaced both at the same time - think it was $700. https://www.mpowermotorsports.org/

you can also hit up http://www.rebuild.org.uk/ the original supplier or these rebuilt units.

Are you in the facebook BMW E9X M3 V8 owners club group? lot of resources and knowledgeable guys on there as well and pretty quick to respond.

[strokemycocktus]

Ok, I have checked the battery, it was reading 11.9-12V with ignition on and lights off. I have no comfort access or angel eyes cut off at this moment, but it was happening earlier along with the increased discharge messages. I took the battery out and charged it - 12.2V after that. Drove the car a bit (a few short trips with some stops) and got limp mode again at the end of the day (immediately after a warm startup). Engine off and on and it was gone like always. The battery dropped to 12V again after one day. My guess is that the battery is done.
I want to get an AGM one, looks like I am left with 2 options - FIAMM 90Ah 900A (identical as OEM BMW), Banner 92Ah 850A (also found as OEM) or VARTA 95Ah 850A. I was told that VARTA makes the best batteries, but I am unsure if it can fit with those parameters? There is no 95 Ah equivalent along OEM batteries - only 90 and 92 Ah.

Faults this time
CDC0 DME: Throttle actuator CAN message, bank 2
2B2D DME: Throttle valves, initialization, bank 2

I have an OBD cable and a Windows computer. I use Reighold ISTA, but couldn't find live data for O2 sensors there. Not sure if this stuff is capable of reading this data.
I have made all the tests that were suggested by the program - all TA testing was correct again.

Water in trunk - I have disassembled all the lining on the right side - everything was dry and had no traces of water. There is just a pool of water under the battery and literally nothing else. The drain plugs are factory sealed and there is no way they could leak. Maybe it's the lamp washers, I don't know. I have put paper towels all around the battery and hopefully I will be able to see something more after it rains or I wash the car.

Of course I know there is a chance that my bank 2 TA is failing and causing the symptoms, but clearly the battery is dead too so I think I'll address that in the first place and see if anything changes. If then the TA errors show up again, I think I'll need to take care of this crap. I know about the rebuild services and I intend to send my TAs to rebuild.org.uk since I am in Europe.

I couldn't find the Facebook group you mentioned, could you please DM me the link?

For now I would appreciate some feedback regarding the battery - is mine actually dead already and which one of the three I mentioned is better. Thanks!

[ItsGary]

Originally Posted by strokemycocktus

Ok, I have checked the battery, it was reading 11.9-12V with ignition on and lights off. I have no comfort access or angel eyes cut off at this moment, but it was happening earlier along with the increased discharge messages. I took the battery out and charged it - 12.2V after that. Drove the car a bit (a few short trips with some stops) and got limp mode again at the end of the day (immediately after a warm startup). Engine off and on and it was gone like always. The battery dropped to 12V again after one day. My guess is that the battery is done.
I want to get an AGM one, looks like I am left with 2 options - FIAMM 90Ah 900A (identical as OEM BMW), Banner 92Ah 850A (also found as OEM) or VARTA 95Ah 850A. I was told that VARTA makes the best batteries, but I am unsure if it can fit with those parameters? There is no 95 Ah equivalent along OEM batteries - only 90 and 92 Ah.

Faults this time
CDC0 DME: Throttle actuator CAN message, bank 2
2B2D DME: Throttle valves, initialization, bank 2

I have an OBD cable and a Windows computer. I use Reighold ISTA, but couldn't find live data for O2 sensors there. Not sure if this stuff is capable of reading this data.
I have made all the tests that were suggested by the program - all TA testing was correct again.

Water in trunk - I have disassembled all the lining on the right side - everything was dry and had no traces of water. There is just a pool of water under the battery and literally nothing else. The drain plugs are factory sealed and there is no way they could leak. Maybe it's the lamp washers, I don't know. I have put paper towels all around the battery and hopefully I will be able to see something more after it rains or I wash the car.

Of course I know there is a chance that my bank 2 TA is failing and causing the symptoms, but clearly the battery is dead too so I think I'll address that in the first place and see if anything changes. If then the TA errors show up again, I think I'll need to take care of this crap. I know about the rebuild services and I intend to send my TAs to rebuild.org.uk since I am in Europe.

I couldn't find the Facebook group you mentioned, could you please DM me the link?

For now I would appreciate some feedback regarding the battery - is mine actually dead already and which one of the three I mentioned is better. Thanks!

https://www.facebook.com/groups/1281...429/?ref=share

[strokemycocktus]

Thanks for the link Gary.
A few updates - I have installed a new VARTA 95ah AGM battery yesterday - no faults and No problems so far. Only thing is that the voltage just after installation was 12.1V - should I charge a brand new battery or what?
I have registered the battery replacement, but was unable to code the large capacity (it now says 90ah) - NCS Expert throws me an error when I try to change the "battetie klasse" record.

Also I have put a shitload of paper towels around the battery and I have a pretty accurate leak location - it's the corner above positive cable (shown in picture below). What can it be? Fuel door?

EDIT: I have just read that the battery capacity can be coded to 80Ah, 90Ah, etc. So guess I'm ok with those extra 5 Ah?

[strokemycocktus]

Car ran fine with the new AGM battery the whole week, until Friday when I got a series of limp modes one after another. Codes attached.
Nothing O2 sensor related, so it could be that a worn battery was causing it as someone suggested. But nonetheless, it looks like my actuators took a shit too I'm sending them to "rebuild" in the UK in about 2 weeks. Hopefully the whole horror finally ends.

In the meantime, I have soaked 3 microfiber towels of water from the battery compartment again

[krx927]

Last year I was also getting O2 cuts and car was going into limp mode.

It turned out that it was a faulty gasket on the exhaust just before o2 sensor. Cheap repair!

[strokemycocktus]

Originally Posted by krx927

Last year I was also getting O2 cuts and car was going into limp mode.

It turned out that it was a faulty gasket on the exhaust just before o2 sensor. Cheap repair!

Thanks for your input. Do you remember if you had throttle actuator faults as well?
I am getting mostly TA faults but from time to time O2 sensor shows up too. TAs are both banks, O2 always bank 1. Not sure what is causing what and where to start...

[strokemycocktus]

Update - I have replaced both TAs with refurbished ones from Jason at Rebuild. I've been driving for only like one day so far so it's probably too early to coment on faults and limp mode, but man, the car is transformed with new actuators. I don't know how, but the shifting is more effortless and smoother, the car idles a lot smoother and starts softer too. It also revs quicker. I totally didn't expect such difference, guess my old actuators were crap. I noticed that the one on the driver side would block somewhere around it's neutral position, so probably there was something going on with the gears.

I have also swapped the O2 sensors left to right, we'll see what kind of faults now show up.

Anyway, I hope I get no more limp mode and I enjoy driving the car even more with its new performance

And about the leak in the trunk, I have replaced the fuel cover bowl, the old one looked a bit crappy so I'm 99% positive this was the cause. I need to wash the car to confirm though.