Need some help interpreting OBD-II codes (increased emissions)

Car seems to drive normally / no limp mode / reduced power.

Initial codes found:
P0030 - HO2S Heater Control Circuit Bank 1 Sensor 1
P0050 - HO2S Heater Control Circuit Bank 2 Sensor 1
P0132 - O2 Sensor Circuit High Voltage
P0171 - System Too Lean Bank1
P0174 - System Too Lean Bank2
P2626 - O2 Sensor Pumping Current Trim Circuit/Open Bank1 Sensor 1
P2629 - O2 Sensor Pumping Current Trim Circuit/Open Bank2 Sensor 1

Cleared codes and drove about 10 mins:
P0030 - HO2S Heater Control Circuit Bank 1 Sensor 1
P0050 - HO2S Heater Control Circuit Bank 2 Sensor 1
P0132 - O2 Sensor Circuit High Voltage

(One might think O2 sensors are bad?)

Then these are added as pending:
P0030 - HO2S Heater Control Circuit Bank 1 Sensor 1
P0050 - HO2S Heater Control Circuit Bank 2 Sensor 1
P0106 - MAP/Barometric Pressure Circuit Range/Performance Problem
P0155 - 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

(Now the MAP sensor may be the culprit all along or perhaps a vacuum leak?)

I ordered two O2 sensors and have them in hand but hate to replace them if they are not the culprit. Any thoughts?

Some of them are posted here. I'll see if I can look up the others later tonight.

http://www.m3post.com/forums/showthread.php?t=928325

regular_guy:
Thank you for the reference here (I think I've seen it in my search) and appreciate the effort looking the others up. I see that there are multiple BMW specific codes for a single Pxxxx code. I guess I need to see if I can fire up INPA to try and narrow it down instead of my standard OBD-II tool.

For P0106:
"Check induction system B1 for leaks"

Any reference for what B1 comprises in terms of checking for leaks?

I am trying to be as self sufficient as I can, as such...where are you looking the codes/cross reference? I have some BMW info sources in my collection, having owned a '98 318ti but wasn't sure they would apply to the newer E90. What are other good references for troubleshooting OBD-II? I am a fairly adept OBD-I/pre OBD-II DIY'er on my Mazda project track cars since those codes are usually very specific and point to one specific component as faulty.

bond_007 wrote

Car seems to drive normally / no limp mode / reduced power.

Initial codes found:
P0030 - HO2S Heater Control Circuit Bank 1 Sensor 1
P0050 - HO2S Heater Control Circuit Bank 2 Sensor 1
P0132 - O2 Sensor Circuit High Voltage
P0171 - System Too Lean Bank1
P0174 - System Too Lean Bank2
P2626 - O2 Sensor Pumping Current Trim Circuit/Open Bank1 Sensor 1
P2629 - O2 Sensor Pumping Current Trim Circuit/Open Bank2 Sensor 1

Cleared codes and drove about 10 mins:
P0030 - HO2S Heater Control Circuit Bank 1 Sensor 1
P0050 - HO2S Heater Control Circuit Bank 2 Sensor 1
P0132 - O2 Sensor Circuit High Voltage

(One might think O2 sensors are bad?)

Then these are added as pending:
P0030 - HO2S Heater Control Circuit Bank 1 Sensor 1
P0050 - HO2S Heater Control Circuit Bank 2 Sensor 1
P0106 - MAP/Barometric Pressure Circuit Range/Performance Problem
P0155 - 02 Sensor Heater Circuit Malfunction (Bank 2 Sensor 1)

(Now the MAP sensor may be the culprit all along or perhaps a vacuum leak?)

I ordered two O2 sensors and have them in hand but hate to replace them if they are not the culprit. Any thoughts?

It looks like I can get you answers on the following (later tonight):

P0030
P0050
P0132
P0171
P0174
P2626
P2629
P0106
P0155

It looks like I can get you answers for all of them. Just sit tight, it might take a while to get them all together. Hopefully I will get them all done tonight.

bond_007 wrote

For P0106:
"Check induction system B1 for leaks"

Any reference for what B1 comprises in terms of checking for leaks?

There's a few BMW techs on the forum. Hopefully they can help you with this.

This is all I could get done tonight. I'll try to finish up tomorrow night.

P0030 - 273E, Post-64
P0050 - 273F, Post-65
P0132 - 2724, Post-66
P0171 - 275D, Post-67
P0171 - 27BA, Post-68

bond_007 wrote

regular_guy:
Thank you for the reference here (I think I've seen it in my search) and appreciate the effort looking the others up. I see that there are multiple BMW specific codes for a single Pxxxx code. I guess I need to see if I can fire up INPA to try and narrow it down instead of my standard OBD-II tool.

For P0106:
"Check induction system B1 for leaks"

Any reference for what B1 comprises in terms of checking for leaks?

I am trying to be as self sufficient as I can, as such...where are you looking the codes/cross reference? I have some BMW info sources in my collection, having owned a '98 318ti but wasn't sure they would apply to the newer E90. What are other good references for troubleshooting OBD-II? I am a fairly adept OBD-I/pre OBD-II DIY'er on my Mazda project track cars since those codes are usually very specific and point to one specific component as faulty.

I'm pretty sure "B1" means "Bank-1." Look at the descriptions I just posted and some of them might make more sense now.

It appears as if two new front oxygen sensors was the cure. I used two Denso sensors/ended up being somewhere around $100 each because the Bosch part numbers were on backorder/out of stock everywhere within 100+ miles.

FWIW, the Denso sensor has the same or very similar part numbers as the BMW OEM I removed (Bosch LSU) which seems to be contrary to advice I read on here stating that they were not the same.

The whole job would have been a piece of cake if it weren't for the bracing/skid plate I had to remove to get to the O2 sensor connectors.

Before I reset it after repair, the last batch of codes went to just P0030 and P0050. It seems as if the car will throw and/or clear codes itself? I think the pressure sensor one may have been tripped by a funky idle oscillation (it might need an idle valve).

Parts may be somewhat pricey but at least service is intelligent and reasonable on the E90 chassis.

Thanks for the help!

No need to remove the front skid plate; you can pull the center and rear bolts and gain enough clearance. However, on the driver's side, you do have to remove a very small angled small heatshield.

What mileage do you have? I replaced my primary 02 at around 50k miles after getting some codes. Also got a fuel code around the same time and replaced the sensor by the driver's front shock tower. No codes in 10k miles since.

Seems like all is well. I was able to pass NC inspection on 8 of 9 indicators ready and got my tags renewed before incurring penalty (tags + taxes together from here on out) ... so, if the dreaded SES comes back again, I have plenty of time to deal with it.

Thanks for the tip (in case there is a next time, hopefully not). I tend to over disassemble to get a good look at things and left the panels off and still need to put them back on (thinking that the sensors wouldn't fix it and would have to do further diagnosis on wiring or DME). Power tools made light work of the extra hardware, plus I figured I should take a look underneath to see what the heck was going on (very small oil leak located) with the car given I have not had hands on it like my other projects (93 RX-7 and 90 Turbo Miata). I think the heat shield you are talking about was what the passenger connector was attached to? Stuff like that tended to be gone from other cars by the time I got to them.

I am at 90k and replaced the same fuel pressure sensor a few months back, maybe 5k ago. I was worried that one was the pump or the pump controller.

I find it strange that the sensors are going bad. Usually don't have that sort of issue with my Mazdas. I did have to replace the crank sensor on my E36 318ti, so I guess it is par for the game.

Once I add windshield washer fluid, the dash will be absent of all service lights (for a change) and then maybe I can start work on getting the Mazdas in shape for track events!

bond_007 wrote

Seems like all is well. I was able to pass NC inspection on 8 of 9 indicators ready and got my tags renewed before incurring penalty (tags + taxes together from here on out) ... so, if the dreaded SES comes back again, I have plenty of time to deal with it.

Thanks for the tip (in case there is a next time, hopefully not). I tend to over disassemble to get a good look at things and left the panels off and still need to put them back on (thinking that the sensors wouldn't fix it and would have to do further diagnosis on wiring or DME). Power tools made light work of the extra hardware, plus I figured I should take a look underneath to see what the heck was going on (very small oil leak located) with the car given I have not had hands on it like my other projects (93 RX-7 and 90 Turbo Miata). I think the heat shield you are talking about was what the passenger connector was attached to? Stuff like that tended to be gone from other cars by the time I got to them.

I am at 90k and replaced the same fuel pressure sensor a few months back, maybe 5k ago. I was worried that one was the pump or the pump controller.

I find it strange that the sensors are going bad. Usually don't have that sort of issue with my Mazdas. I did have to replace the crank sensor on my E36 318ti, so I guess it is par for the game.

Once I add windshield washer fluid, the dash will be absent of all service lights (for a change) and then maybe I can start work on getting the Mazdas in shape for track events!

That's good news. I still plan to finish posting info on the remaining errors. But glad it all worked out.

regular guy wrote

That's good news. I still plan to finish posting info on the remaining errors. But glad it all worked out.

Thanks and thanks for posting them. Will read through them. I figure they probably pointed to the same diagnosis.