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Help with OBD II codes, diaognostics ??

03-30-2009, 04:16 PM
I hope some one can help me. I'm struggling with diognostic codes that keep triggering the SES lignt (not the MIL / EML light though).

Car is an '05 X3 2.5 gas, 70k miles.

I have a generic reader, and a Peake Reserach reader. Apparently the Peake reads fatory BMW codes.

Here's the problem; the Peake code list shows the same code for multiple problems. From the the Peake I'm getting:
Code 20 (Idle control valve stuck, or #6 injecter malfunction) +
Code 2882 (Outlet Fuel Press Control valve or Mixture Preparation Bank #1) and
Code 2883 ( Fuel Rail Press Regulation or Mixture Preparation Bank 2)
Code 276d.....several choices having to do with tank venting or leaking.

It has a slight miss on start up, hot or cold. The fuel press at the rail checks fine at 3.5b, steady and doesn't leak down, engine off. Plugs look fine.

I have an OE manual (TIS CD), but I can't find any dignostic codes in there???? Where are they?

M Generic reader gives me codes 171 and 174 that have to do with "Lean mixtiure, bank #1 and #2.


Thanks, MK


04-02-2009, 12:10 PM
Can anyone refer me to a tech oriented forum??

04-06-2009, 08:55 PM
It looks like you have an Evap leak. I suggest using brake cleaner and spraying along the intake manifold, intake air boot, DISA valve, and as best as possible under intake manifold and listen to the engine for a change in idle. Most likely cause is the air boot is cracking, oil/vapor seperator is leaking or DISA valve. Good luck,

04-06-2009, 09:00 PM
I believe this will help you and is something you are looking for. www.obd-codes.com

04-06-2009, 09:08 PM
Thanks a lot. I've been all over it for Vacuum leaks.....but have not tried your "spray and listen technique". I'll check the other items too.....but I'ver eyeballed the boot up to the light and stretched.....looks tight.


04-06-2009, 10:19 PM

Can you tell me if the DISA valve is the cause or if it's a likely vacuum leak? I ask because it looked like a possible vacuum leak at the big seal where it plugs into the manifold. So I have cleaned up the valve internally, made sure it was free, checked that its diaphram was not leaking in the actuator and then resealed it to the manifold....no effect on rough starting idle or codes produced (Mixture issue on both banks). Could the aDISA valve malfunction cause the code I'm seeing? Or are you just concerned about the vacuum leak?

One more clue; this car was in Las Vegas, lots of sand/dust. When I bought it at 70k miles, it was still on the 1st air cleaner (codes were present) and there was sand everywhere. Inside the intake manifold with the DISA valve out, I find more grit/sand than I'd expect. At first, I thought it came in through the air filter (now replaced along with all fluids).

THanks a lot HiKinTech.....you are on to something.


04-10-2009, 07:39 PM
Sorry it took so long to get back to you. I do not get on this site that often. Normally the leak is coming from the seal between the intake manifold and the DISA valve. When you had the DISA valve out was the flap ok? The pin falls out and the flap will not operate properly. I'm not use to the codes you provided (most likely due to the tester), but I believe the 2882 & 2883 are indicating a fuel mixture problem. Normally on that engine its a lean issue (unmeter air). I listed off the most common issues and 70,000 miles sound like the DISA valve. I reread you OP and the only other cause for concern would be the 276D Tank vent valve. If this component was open all the time you would get unmetered air. I believe that code 20 is being cause by the other faults, but if you wanted to prove that one out, swap injectors from cyl 6 to another cyl. I hope this helps - it's really difficult for me to tell you to replace any component from my computer. You need to prove that the component is the cause. With that said, if you ran the vehicle and sprayed the cleaner around the DISA valve and the idle changed that I would go with a DISA valve, if the flap inside the DISA valve was damaged then - replace DISA valve (weather or not it fixes for issue, it bad). I hope this helps. I will check back on this post probably tomorrow. Good luck.

04-11-2009, 12:58 PM
Thanks HiKin,
It turns out the code 20 is really the table #20 for the peake tool.......but before I understood that I did swap the injectors 1 to 6 with.....as I now know I should have expected, no effect. As for the DISA valve.....its butterfly looks ok and operated with vacuum and is now clean and sealed to the manifold housing....no effect, so I doubt that's it. Bu I haven't yet taken a good look or spray around the air/oil sepataor and that's next. Also, the 276d code makes me wonder if a hose is off or loose in the right rear fender well where the fuel tank vent components exist. I now recall seeing that the RR shock absorber cove had some scrubbing damage apparently from a blown tire rubbing......so it's concievable that the plastic liner got bounced around and upset something in there....I'll investigate that too. Will let you know next week.......and THANK YOU very much for your help. Mike

04-19-2009, 11:55 AM
HiKin, and all/anyone who can help:
Well....I spent the better part of a day in there yesterday. I rechecked all the possible vacc leak locations. All the hoses, boots and rubber are pliable and soft. There is no indication of any moisture anywhere. In particular I checked all the items you stressed (boot, DISA and Oil separator valve).
1)The boot, out of the car and held to the light, shows minor external surface cracking ....but no through cracks.
2) DISA is clean, free do move, B'fly rotates when I blow on the external accum vent....and it's internal diaphram doesn't leak through; although connecting and disconnecting the electrical plu at idle has no effect other than to trigger a code......is this the right response? Last, it fits snug into the housing and doesn't respond to liquid (wd40) spray around the outside joining surface with the manifold.
3)The Oil Separator id the hardest to judge and get to. But it's clean and dry (covered by a molder rubber boot that seems to be a thermal protector). I can peel the boot open and it's dry in there too. All hoses connected tight. While idling, I can fiddle the boot and hoses with no effect, I can't hear any succing there or elsewhere either. Since the hose from the valve cover breather is pressurized, I would think that were there leakage.....I see some eveidence of oil.......but none. Can't really spray it much.
4) I used WD-40 to spray (no effect).....are you suggesting carb cleaner for a particular reason??
5) As you suggested.....trying to judge the intake m'fold to head gasket for leakage is a limited proposition.
6) Checked the tube al the way back twords the RR fender locaion of the feul tank vent equipment (remember I once, and only one time found code 276d indicating a leak in the fuel tank venting system). Nothing obvious.....but I didn't go into the fender well as I have to cut all the trim rivits a nd theres no code replay.
7) still getting the same two codes indicating "mixture problem Bank 1 and 2".

I'm now wondering if it's something other than a vacc leak. ???

I note now that the "rough inital idle" that occurs on start up for just a few seconds and then clears, is predominately if not totallly limited to cold or cool starts. It's not there much at all on warm start. But, I can recreate the codes after just a few minutes of idle time just sitting there in the garage......very consistantly. So whatever is the trigger.....it's right there every time.

Where do I go from here???
a) could DISA valve malfunction (not leak) be a factor? I'd think this valve actuates at speed.
b) I could have the induction system "smoked"?
c) could I be fooling with a bad MAF sensor?
d) ??? perplexed.

I'd consider a trip to the dealer.....but am even more fearful now of a costly mis-diagnosis and multiple visits that I'll regret.

Thanks for any thoughts.

04-19-2009, 11:15 PM
See the problem here is we do not know which way the mixture faults lies (rich or lean). I have been going off of the assumption that is lean (because that is a lot more commom). With a BMW diagnostic equipment you can tell by checking the adaptation values. These are a set of number that are either positive or negative. It a learned value by the DME. The DME uses this to know how much fuel to inject. Very similar to what the domestic manufacture use with short term and long term fuel mixture.

I have had you check everything that could cause a lean mixture. I guess now we need to check for a rich mixture. This is not as easy. The most likely cause is the Air mass meter. Unfortunately the only way to know is to swap out with a new one. First, I would recommend checking the engine air filter. Make sure it is not dirty. Note: When you find the component that is causing this you will have to clear the fault and drive it for quite some time, since you cannot clear them with your scan tool. The DME has to relearn itself back down.

You may after all have to take it to the dealership. They should be able to pinpoint the component.

04-20-2009, 04:50 PM
See if this gives you a clue as to lean or rich;
But first....it's had an air filter change as part of the troubleshooting with no efect at all......and the old one was really dirty, possibly 70k miles on it.

Next: It does has a rough stumble at idle on start up, more pronounced at cold start. The idle smooths out in about 2 seconds or less to a normal mode. While looking for vacc. leaks, I had the air filter housing out, MAF in place with engine at idle. I noticed that if the MAF housing fell out of the boot while I was reaching down in there looking for vacc. leaks, after a few seconds, the idle would get rough just like at start up. I would think this to be a lean condition in that the MAF seeing no air flow would begin to meter fuel way back......and I got a similar studder idle.

On the other hand, I'd think things would naturally be pretty rich on a cold start......vacc leak or not......so studder idle associated with rich condition.

Last - plugs look normal.

Does that help at all?

Is any of my thinking and observations in my prior post off base??

Thanks again,

04-20-2009, 07:21 PM
First to answer your question on the pervious post.
a. If the everything is in working order for the DISA valve then it is not your problem.
b. If you can get the induction system smoked that you be great. You would know for sure if your have a leak causing a lean concern.
c. At this point I beginning to believe that you have a bad MAF sensor. I've seen them do some strange things.
d. I'm becoming perplexed also???

As far as the rough running at first cold start, this is kindof normal to a point. But I believe that it probably is a little worse that normal because the DME is in an open system and dumping fuel into the cylinder. Then it goes into close loop and it finds it's bearing enough to not cause a misfire. Have you been driving this vehicle while you are trying to repair it.

I'm afraid that I'm running out of ideas for you to try. You may want to start thing about taking it to the dealership or a good indepentant shop that has the BMW diagnostic equipment. There are some out there.

04-20-2009, 09:35 PM
Hikin.....it's really great of you to take the time.....Thank you again.

I may just have to have it smoked.....but my indi guy will charge me about $100 and I'll need to trade that off against parts (an MAF) and take my chances.

More info for you to ponder;
a) Yes we have been driving and trouble shooting for the 4-5 weeks since we got it with the SEL on.
b) My Peake Performance BMW reader will clear the codes, so I've done that over and over. I'm really surprised that it will pick up the codes again so quickly.....but it does.
c) Lean or rich?: Well, I looked back over my notes and the first post and I have codes from the Paeke that are "Mixture Preparation Bank 1, 2" and I have codes 0171 and 0174 from my generic reader that are "Lean mixture bank 1, 2"......so that's part of where we jumped to that lean conclusion. You are right of course that the generic reader will not reset the SEL.
d) The rough idle: if it weren't for the SEL and codes, I might think it was about normal. But our '01 135k mile X5 3.0 doesn't start this way. The MAF is different or I'd have swapped it by now.

e) Here's another choice: drive it a lot more and see if it doesn't trigger another fault that will give me a clue.Think there's much of any risk given that it might be a bit lean? Driuveability and the plugs are fine. If it's lean or rich.....it seems to be only at start/idle??

Either e) above or it sounds like it may be time to gamble some more $$ ....

Let me know any further thoughts or trouble shooting isolation methods/ideas.

Thanks again,

04-20-2009, 10:13 PM
If you are pretty positive that it is a lean mixture. Have the system smoked. You will surely pinpoint the problem. Unless, going back to the first post. The tank vent valve is stuck open. This valve (if I remember correctly) in attach to the manifold. It should have a hose in and a hose out. Two to maybe three wires. If this is stuck open then you will have a lean mixture fault(this is very seldom, but it does happen).

I am not saying that at startup you should have a rough idle. I was just hinting at it being more than normal. But I'm sure what you are experianing is more than normal.

It wont hurt the engine any if you drive on it when it's running lean. But you probably will not be able to smog it. But, it the lean mixture turns into a misfire, which it can if it gets bad enough then you could start to cause engine damage. If it was my car. I would clear the faults and drive it until the check engine light came back on. Then continue from there. I will give it some thought tomorrow and run it by a couple people.

04-20-2009, 10:40 PM

I will check the Tank Vent Valve.....it's right in front and easy to check. I gather it should normally be closed ?

I have been clearing the codes and driving over the weeks.....they come back with high repeatability. The SEL take 20-40 miles though.

Last; when I pull the DISA valve, I'm a little surprised to find a bit of sand/grit in the oil film on the inside. That surprises me that grit would get through the air filter....but not impoisible.....it had been in Las Vegas and came with a lot of sand in the engine bay and in the bottom (dirty side) of the air filter box. I mention this because it would imply a source of vacuum leakage. But if there is a leak.....it must be small.

I'll drive for a while and then smoke it. If I can get my hands on another 2.5i, I'll try and swap the MAF.....but at over $300......it would seems like a bad bet/buy at this point.


04-23-2009, 07:55 PM
I just had a vehicle today that has mixture too lean faults. I smoked the intake and could not find any leaks. I believe that there is an internal leak inside the oil/vapor seperator. I have not performed the repairs yet (awaiting customer approval). Same engine as yours. This may be where your problem lies. Except your original faults you had a fault for the tank vent valve. If the leak is internal that there are really only two possible causes. The TVV or the oil/vapor seperator. If you do the oil/vapor seperator, I recommend that you get all 4 hoses for it also. At the very least the bottom hose going to the drain tube. You normally end up breaking the hoses when removing because they become brittle. I hope this helps.

04-23-2009, 08:47 PM
YES! it sure does help.

I'll be vary interested to know if your Oil Separator leaks internally with no obvious external leakage or oil seepage. I appreciate to comment on the hoses too. I've fondeled every hose in there, none are brittle at all.....but it may still be worthwhile just to make a tough job easier.....and especially the line from the dip stick.

If you do see an internal leak inthe Oil Sepatrator, let me know if there would have been a trouble isolaton I could try (like block one hose for instance) because it's a b__ch to get that bugger out of there.

Please let me know what you ultimately find.

My plan at this point is to:
a) check the TVV based on the odd code (clue??) and because its so easy to check.
b) then smoke it
c) if nothing, and depending upon what you find.....do the Oil Separator. Either this or keep driving for a while and hope for a new code/clue.

Thanks again.

04-27-2009, 01:37 PM
Customer did not buy the repair, so I will not know if it fixed it. Probably will get work done by cheaper place.

04-27-2009, 09:44 PM
Thanks for the follow through.....much appreciated.

I checked the TVV this weekend....and as you suspected......it was closed tight as tight could be. Odd thing though, I had a re-occurance of code 276d....."tank Vent Valve".

I suppose it is possible that the TVV fails to open on occasion, thus triggering the code, unrelated to the lean mixture codes. I'll deal with that separately if that's the case.

All of the Laen/mixture Prep. codes were present as usual along with the TVV code.

Question: while continuing to search for an external vacc. leak, I had the engine at idle and pulled the dip stick......full vacuum in the crank case. Is this normal, or possible confirmation of internal leakage of the Oil Separator valve?

Next question (and after the Q? above): In review of the Vacc/ intake system, I don't see a possible external air flow path from an internal failure of the Oil Separtaor Valve.....where does the vacc. air flow originate if the system is sealed and the crankcase is at full vacc. pressure (negatve pressure) ??

Is any of this pointing to the conclusion you came too on your recent customer car.....i.e. internal leak of the Oil sep. Valve????

Thanks Hikin.........big disapointment on your customer car that we couldn't see it through.


04-28-2009, 08:06 PM
Answer to first question. That's hard to say for sure. How we normally check the oil/vapor seperator is with a tool called a manometer. My shop is new and that is an old tool so we do not have one. We hook up the tool to the oil fill port and run the engine.
2nd question. There is a hose that runs across for intake manifold that eventually hooks to the intake manifold. So you would have unmeter air that way. I normally don't see internal leaks but it does happen.

Do you know if the TVV fault is stuch open or close. If stuck open replace the TVV, this may be your problem.

Sorry, I don't have too much more information for you. I hope you figure it out.

04-29-2009, 10:18 AM
Answer to first question. That's hard to say for sure. How we normally check the oil/vapor seperator is with a tool called a manometer. My shop is new and that is an old tool so we do not have one. We hook up the tool to the oil fill port and run the engine.
2nd question. There is a hose that runs across for intake manifold that eventually hooks to the intake manifold. So you would have unmeter air that way. I normally don't see internal leaks but it does happen.

Do you know if the TVV fault is stuch open or close. If stuck open replace the TVV, this may be your problem.

Sorry, I don't have too much more information for you. I hope you figure it out.

Thanks Hikin, I realize we're about as far as we can go here;

As for Q1 on the Oil Separator: The use of a manometer implies a comparative vaccum measurement at a very low level measured in "inches of water" typically (full vaccum being 28 inches of H2O if I recall. One end to the oil fill, the other end to another location......where? Because if it's to atmosphere, mine will suck full intaker manifold vaccum based on my estimation comparing at various points in the intake.

As for the TVV: the code doesn't speak to open or closed, but the vale is closed tight out of the car, and in the car with the engine at idle or turned off. So I'm assuming that it is "normally closed" requiring a signal voltage to open. If this signal is intermittantly applied by the ECU under some set of conditions and the valve failed to open.....then it triggers a code. But that's a different issue. I'll pull it again and apply 12V to see if it operates and closes.....and I guess I could just replace it.......but it doesn't look like the issue.

Back to the Oil/Vapor: can you refer me to, or post the manometer test and the desired vaccum differential so I can check mine t6hat way? I've not seen this test in the BMW manual.....I'm suspicious of that item but trying to avoid the cost/effort of swapping that part and hoses unless it is confirmed.

Thanks again.

PS: pls PM me you business and contact info. My sister lives in Sacramento and has a whole fleet of BMW/Porsche that deserves good indy care.


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05-03-2009, 10:02 PM
HikinTech got me there with his suggestion that crankcase vacuum ressure should be in the range of a few inches of H2O vacuum; if not the air oil separator was shot/leaking internally.

I found that I had full intake vacuum in the crankcase......you had to pull pretty hard on the oil fill cap with the engine running to get the cap off.....and once off, it was a giant sucking like a vacuum cleaner ....until the crank case pressure equalized. Certainly not a few inches of H2O. I compared it using the palm of my hand as a vacuum gage/manometer.....to the X5 we also have and it was day and night.

Once removed and broken open, the old valve had a tear in the diaphram (to the atmospheric vent port) about 1/3 of the way around.

It's now apparent that the rough idle on start up was due to extreme lean condition as the entire crankcase was drawn to intake vacuum pressue level....once there, after about 1-2 seconds, the mixture returned to/near normal, and the idle smoothed out.

Thanks agian for your all of your great help and all the clues.

BTW: there's a great DYI on replacing the air/oil separator in Bimmerfest.


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