P0313 & P0175. Odd?

Driving around the other night and when I was stopped at a red light the SES light came on. Next day Autozone pulled these codes. P0175 & P0313. That seems like an odd combo to me. Any insight would help?

What are the definitions for those codes?

0175= system too rich bank 2
0313= misfire detected with low fuel

Hmmm, haven't seen that combination. Not enough air getting in? When did you last change the air filter ?

I had those and more, and documented my saga over here, which might help the OP:
- Does the order of the misfire OBDII DTCs diagnostic trouble codes actually matter (1)

I changed the air filter today, I have driven around a little bit and the codes haven't re-appeared. Air filter was a little dirty, but not bad. I cleaned the MAF, and Ill throw a bottle of techron next fill up. When my SES first came on, I thought it was just more cold weather lean code shenanigans, but I was surprised by the codes that popped up. If the codes pop up again, what would be the next best guess at a fix? O2 sensors maybe on the way out, or possibly fuel pump? Any other insight would help.

Update: So after I changed the air filter, I drove around for several days with no problem. I thought my issue was solved, but no. Today SES light comes back up and pulls the same codes. I am out of ideas. Anyone out there have any?

Originally Posted by GLOK1132

Update: So after I changed the air filter, I drove around for several days with no problem. I thought my issue was solved, but no. Today SES light comes back up and pulls the same codes. I am out of ideas. Anyone out there have any?

Treat it like any other set of codes. Methodically work the problem. 0175 code is likely a vacuum leak or something along those lines. Check your intake tract from MAF to TB for cracks. Check CVV for cracks, check Valve cover for leaks, any of these can cause your issue.

As for the misfire likely a by product of the car trying to correct for the unmetered air getting into the system.

Agree with likelihood of a vacuum leak, but here are many other conditions that can cause the same:

http://www.obd-codes.com/p0175

http://repairpal.com/OBD-II-Code-P0172-and-P0175

http://forum.e46fanatics.com/showthread.php?t=616343

Update: Last night I filled my car up and this morning my SES light went away. The first time the light came on was when my low fuel light was on, I cleared the codes and filled it up, and the codes didn't come back until I was at about 1/4 of a tank. Is this a sign my fuel pump is crapping out on me or is something else at fault?

Originally Posted by GLOK1132

Update: Last night I filled my car up and this morning my SES light went away. The first time the light came on was when my low fuel light was on, I cleared the codes and filled it up, and the codes didn't come back until I was at about 1/4 of a tank. Is this a sign my fuel pump is crapping out on me or is something else at fault?

You're guessing.
If what I read is your logical thought process, you may as well put the scores of causes for SES lights 10 feet away, close both eyes, shut down your logical thought process, and throw a dart - then write back here that you think that's the problem.

Your low fuel light will have nothing whatsoever to do with anything in 99.9% of the cases - so, let's look logically at your problem, shall we?

The fact the light went away, simply means that you have an intermittent problem. Do you know how that works? You have to understand in order to diagnose. And you have to think.

Let's think about WHY the light went away.

Other threads cover this in gory detail, so here's just a summary of what happens with that SES light.
a) Everything OBD related is fine ... there are no pending codes & no SES
b) Something OBD related goes wrong during a FTP drive cycle ... pending code triggered
c) Something OBD related goes wrong during the next FTP ... another pending code
d) That something goes wrong a third time ... bingo! SES
e) You drive another FTP ... no problem occurs ... SES still on (-1 on pending)
f) You drive yet another FTP ... no problem ocurs ... -2 on pending so SES goes off
g) Now you're back to step a above ... or ... b (you don't know which yet)

So, the fact your SES went off merely means you went two successive FTP cycles w/o the problem occurring. Is it fixed? Maybe. Will it come back. Depends, but probably.

So, here's what you're SUPPOSED to do.
1. You pay $25 for a code reader
2. You check the codes (pending codes are important!)
3. You monitor the situation

If/when the codes are thrown, you START with the codes.

But, remember, the code simply is a starting point. It simply means the sensor in question received a bad power, input, or output signal.

BTW, you have an intermittent small vacuum leak.

Thank you Bee. I was not 100% guessing, I was proposing a hypothesis based off of intermediate level automotive knowledge. I suspected the fuel pump because the codes only seem to come up when:

A. there is less than 1/4 of a tank of gas (hence the low fuel light).
B. It is less than 50 degrees outside (points to small vacuum leak, but I have done a thorough check and have found none)
C. Idling while in gear, such as a red light or drive through window. (I hypothesize that the fuel pump is not regulating proper fuel flow for the low RPM while idling)

I have replaced the Air filter and the DISA o-ring. I have cleaned the MAF and the ICV. I have new spark plugs and a new fuel filter. I have checked my intake boots for small cracks and found nothing. I have looked at the CCV hoses, but I can only see so much without removing them. It is possible that there is a small crack in one of these hoses that I have missed. My next course of action is a more thorough inspection of the CCV system.

I posted here after much searching and reading to receive more in depth knowledge (You have helped greatly with this, for that I thank you). I have come to the conclusion that If my fuel pump was on it way out, then I would have more easily recognizable problems.

I understand that for those of you that contribute highly to this forum (Bee, Bob, Smolck, and many more) that people posting the same questions over and over again is very annoying. I myself search at least 10 times before asking once. But when I do ask, I am seeking more in-depth knowledge and this site has members that posses that knowledge in spades. I apologize if I appear to be another noob asking the same old questions. I am just wanting to improve my own knowledge base so that I can better maintain my precious BMW.

It wouldn't hurt to try a new fuel pump. I can tell you that they ALL fail around 100k-150k miles and are one of the few parts that will leave you stranded when they break. My car got a phantom lean code from time to time before the pump died. I never put 2 and 2 together before it happened. After I replaced it and the code never showed up again I thought, "ah yes, that must have been it".

www.oembimmerparts.com has the VDO pump for our cars very reasonable. Not money wasted IMO.

Keep in mind that a vacuum leak can be found at places other than the "intake" - for example: CCV, Valve Cover/VCG, SAP, etc. Any source of leak between the MAF and the O2 sensors could be the culprit. My dart board guesses in order of likelihood: upper/lower intake bellows (you have to physically pull them off for thorough inspection, not just shine a flash light on them in situ), CCV, vacuum lines on/around the Valve Cover, Valve Cover Gasket, Valve Cover.

Good luck!