Service Engine Soon light

[prowlerflyer]

So pretty much right as I crossed 100k miles I got a Service Engine Soon light. Is this light triggered by mileage? I do not have a code reader and otherwise will have to go to a shop to get it read. Oil service interval still reads 8k, and I don't know if that even trips the Service light. The car otherwise is running fine with no obvious faults. Thoughts?

Steve

[Oli77]

Perhaps make phone calls to local part store. In some states they read codes for free.

[telijah]

Yeah, if the light tripped and car seems OK, it's either something minor, or was a temporary situation and will clear itself in a couple driving intervals. Best to get to a local parts store and as mentioned, see if they'll scan em for free.

For fun, I am gonna guess either a Camshaft Pos Sensor (exhaust side) or lean conditions (vacuum leak). If you haven't done a coolant system refresh, it may also be a failing t-stat... does your car take too long to get the temp needle to 12 oclock?

[prowlerflyer]

Nah, the car exhibits all normal operations. I agree it may be something minor (fingers crossed), but really wanted to make sure BMW hadn't built in for that light to trip via mileage also. My wife's Volvo does (although it says Service Interval). I have since payed very close attention to any signs of anything out of spec, but nothing. We'll see if I can get the code read this weekend. I have heard CPS fail, but I figured there would be a degradation in performance. The cooling system was completely done at 80k and I am at 100k now, so that should be good (knock on wood).

[acontzhp]

Check your intake boots. I've had both tear on me. Also it can be your DISA valve. I replaced my own at 86k, engine light came on with no other symptoms. My DISA valve was shot it had absolutely no resistance and I could have been bad if something would have broke off and gotten sucked into the engine. P0171 and P0174 are the codes that would lead me to suspect one of these parts needs to be inspected and replaced

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[prowlerflyer]

One thing about the TS2 kit, it eliminates the DISA and stock intake boots are replaced with a short silicone one. I will give it a look over though.

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[prowlerflyer]

Ok, the car is throwing codes P0171 & P0174.

The store doesn't have BMW specific codes, but possibly O2 sensor lean condition?

Thoughts?

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[Oli77]

Isn't that the famous: "there's a tear in my boot"? check intake boots for tears. You have to take airbox, maf and the tubes out.

[prowlerflyer]

Noticed searching that those codes can likely be intake boot leaks. I looked it over good the other day and it seemed pretty solid, but I'll check again.

The only intake spot I am not totally satisfied with is the clamshell seal on the airbox halves. I just put in a new air filter before the trip down and was not totally happy with how it fit back together.

That is prior to the MAF though, so it shouldn't cause a lean condition though, right?

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[cakM3]

Steve,

This can be a possibility......"a hole in the intake boot. The piece that goes into the engine side there is a little hose that splits off. Mine had a 3 inch hole in the small tube. I patched it up with tape and waiting to get back in when I have time. The check engine light hasn't come back since though. Try to feel back in there before you tear into the engine. The hole I had was very obvious."

Here is the link: http://forum.e46fanatics.com/showthread.php?t=914540&highlight=p0171+code (http://forum.e46fanatics.com/showthread.php?t=914540&highlight=p0171+code)

1. P0174 - System Too Lean (Bank 1)
2. P0171 - System Too Lean (Bank 2)

If both banks are running lean you have a vacuum leak...try spraying some carborator cleaner (with car running) all over the intake, airbox connections, maf, especially the "y" pipe (runs from maf to throttle body, black rubber large diameter hose), do not forget the brake booster as it is also vacumm assisted. If you hear the engine pick up idle speed at any given point you found your vaccum leak.

Because you're throwing codes for both banks, it's most likely a vacuum leak. Its probably an upstream vacuum leak because it affects both banks. One culprit is the crankcase vapor system (I think its referred to as the oil separator on this engine), another are the intake boots. I would see if you can find anything visually Steve :thumbsup

Here is another reference link: http://forum.e46fanatics.com/showthread.php?t=339495&highlight=p0171+code (http://forum.e46fanatics.com/showthread.php?t=339495&highlight=p0171+code)

[danewilson77]

Most likely spot......

http://i1015.photobucket.com/albums/af278/nicee46/Maintenance%20and%20Misc/1-18.jpg

[kayger12]

Most likely spot......

http://i1015.photobucket.com/albums/af278/nicee46/Maintenance%20and%20Misc/1-18.jpg

^ Agreed.

I wish this was sent with a Galaxy S3

[prowlerflyer]

I'll see how that picture relates to my system, it's different with the TS2 to a certain degree. Out running errands, but as soon as I get home I'll open her up. Thanks all.

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[telijah]

Ok, the car is throwing codes P0171 & P0174.

The store doesn't have BMW specific codes, but possibly O2 sensor lean condition?

Thoughts?

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Hah, my guess was right in post #3. You've already got plenty of good suggestions on places to look for it, good luck. As for your other question, pre-MAF leaks should not cause this, unless maybe it is a massive one and the MAF cannot account for it, but then I would suppose that big a leak would be quite obvious.

[llll1l1ll]

I'm going to say it's most likely your intake boot(s). The holes are not always clearly visible. I heard my leak, though. A faint whistling sound...

[prowlerflyer]

Well, tore the whole intake down yesterday. Fixed the airbox air filter seal (does that front clip really need to be that big of a pita, BMW?), not bad, but perfect now.

All intake hoses and boot seemed to be in perfect shape. MAF was clean. I am going to try your trick next Charlie, and shoot some carb cleaner around the boot and see if it effects idle.

Attached is a couple of pics of the different boot arrangement with the TS2. Its also a silicone coated and fiber reinforced boot.

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[danewilson77]

Mmm.. Those are better that typical boots. Look like Stec Boots.

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[prowlerflyer]

Will these codes self clear if the problem resolves, or do they have cleared with a reader?

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[danewilson77]

Will these codes self clear if the problem resolves, or do they have cleared with a reader?

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I think you have to clear them.

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[llll1l1ll]

Definitely have to clear them.

[prowlerflyer]

Well I bought the OBDLink Bluetooth Scan Tool and got the Torque app. I then cleared out those two faults. After a day of driving they have not resurfaced.

So, nothing definitive on why I got them in the first place, but everything seems fine now (famous last words right..).

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[danewilson77]

Ok. Give it a week.

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[Nivo]

Since you have the S/C it might have been a small vac leak through the CCV system.

[prowlerflyer]

Since you have the S/C it might have been a small vac leak through the CCV system.

Good thought... Now how to trouble shoot that?

[Nivo]

Good thought... Now how to trouble shoot that?
My leak that gave me a code was coming from the hose between the CCV and the intake manifold port runner..

3848

Part #7 on mine at the clamp was cracked. you can use propane gas or carb cleaner and spray around the area with engine running you should hear a change in engine tone when you get close to your vac leak.