[N0OS3]

I'm getting 3 codes: (i'm out of warranty and i'd much rather fix the problem myself if i can)

P0171 "SYS 2 lean Bank 1"

P0597 "Thermostat control circuit open"

P2195 "02 Signal stuck lean Bank 1 Sensor 1"

The first one, i have no idea what's really going on... i don't know how to run diagnostics past this point.

The second one, Research tells me the $85 thermostat went bad... but where is it located exactly?

The third one, I'm thinking the post-O2 sensor is giving me codes. I only took out the secondaries, which there was no sensor attached... so i'm kind of stumped on this one...

**Also, where do i buy the new brake pad sensors?** P/N?

[gichoke]

Probably other sites, but ECS has a good search tool:

brake sensors:
http://www.ecstuning.com/BMW-E90-325...L/Braking/OEM/

Not sure about the other stuff.

[micah_675]

Clean your MAF and run some fuel system cleaner. As well put some Heet Water Remover in your gas tank as well. You are running lean on Cylinder 2 and the bank 1 is actually your pre-cat sensor. Bank 2 is your after cat sensor. Therefore with both of them corresponding it sounds like your MAF or crap gas. Have you had sputtering and even backfires at all? As well when you hit the gas is the car very sluggish if you get on it hard to start with?

[N0OS3]

Originally Posted by micah_675

Clean your MAF and run some fuel system cleaner. As well put some Heet Water Remover in your gas tank as well. You are running lean on Cylinder 2 and the bank 1 is actually your pre-cat sensor. Bank 2 is your after cat sensor. Therefore with both of them corresponding it sounds like your MAF or crap gas. Have you had sputtering and even backfires at all? As well when you hit the gas is the car very sluggish if you get on it hard to start with?

no sputtering or backfires. I'll run fuel system cleaner today... i never heard of water heat remover... can you get this at a convenience store as well?

The MAF sensor is the clip-on attachment on the intake tube, right?

[N0OS3]

Okay, so O'Reilly's told me to try a few things first before i waste a bunch of money taking it to the dealer...

MAF sensor cleaner... he says try this vs isopropyl alcohol because the alcohol may still leave residue behind. The oil from the aFe intake may have contaminated the sensor thus giving a "bad air" reading.
"Iso-HEET" ... a bad batch of fuel (bottom of the tank) may have put water in the reservoir.
Fuel Injector cleaner... i do this from time to time anyway, but all of these together may make a difference.

I'll post an update next week sometime...

[e90pilot]

I don't think it's a bad post cat O2 sensor. The post cat sensor just detects catalytic efficiency not fuel mixture. The pre cat sensor does that. As far as I know, sensor 1 is the pre-cat. I could be wrong; this car has suprised me before.

[N0OS3]

i ran MAF sensor cleaner over it yesterday and put the ISO-HEET in the tank... i'll have to get the codes cleared after a few days to see if they light back up...

Whenever i get down to half tank, i'll throw some fuel injector cleaner in also.

[edirtaynine]

those arent problems from modding. those are regular maintenance issues from normal wear and tear of having an old car. just sayin.

[N0OS3]

Originally Posted by edirtaynine

those arent problems from modding. those are regular maintenance issues from normal wear and tear of having an old car. just sayin.

The oil from the aFe intake is known to cause problems with the MAF sensor, in some worse cases, people have to buy a whole new sensor $150-$250.

As for the other codes, i had my secondary cat taken off... i haven't heard about problems with this in the past, but i was just considering the possibility