P0171, P0174 resolved

[boywondergq1]

Awesome, I'll check that stuff. I'm not driving my X5 today and I'm at work until late tonight I'm trying to imagine where this thing is. So it's near the intake manifold, after the air box, right?

Originally Posted by CharlieHustleX5

Its not hard to check if the DISA valve is broken. Just unscrew the 2 torx screws and unplug the connector at the top of the unit. Pull the unit out from the intake manifold and look at the flap. Here's what a broken DISA valve usually looks like.

Flap Loose but still in place
Pieces that broke off which hold the flap in place and rotates the flap open and closed.

Close up of broken part.

[CharlieHustleX5]

Yeap, right above where the intake pipe connects to the throttle body. Its a black plastic unit that protrudes from the intake manifold. Use the schematic Wayne posted for some guidance and it'll be pretty apparent.

[bimmerboy12]

OK I popped mine off in 20 seconds but it looks great and the flap functions fine. I guess now I have to replace the fuel filter/regulator and see what happens.

[boywondergq1]

Thanks Charlie. I should clarify that I have the V8 4.4i engine, and I don't see anything that resembles the realoem diagram. The closest thing I see to a DISA valve is here, between the MAF sensor and the intake manifold:

But started poking around this morning, looking for any hoses that have cracks. This wouldn't be the first time I've found a cracked hose causing MIL codes to set off my check engine light. Last time I found a tiny vacuum hose which was cracked running from some air pump used to pump extra O2 to the calalytic converters during cold/startup running temps to burn off unburnt fuel.
Anyway, started poking around, removed some shrouding and cabin air filter box near the firewall and such and found two hoses that were disintegrated beyond recognition. Something to do with crankcase ventilator and/or oil separator, they are way at the back near the firewall:

and here is one of the cracked hoses:


These things would just melt in my hand. So I picked up two hoses from BMW Toronto this morning on my way to work ($150ish CAD!!) and plan on installing them soon. Doubtful this will fix my problem, but I'm here now anyway. I'll keep poking around, but I don't have a smoke machine to test for an air leak. Checked the dipstick and oil cap also, they seal fine.

Here are my codes, for those interested:



and after a clear I get 'EVAP not ready' and 'CAT not ready' (not pictured):

[Penguin]

Originally Posted by boywondergq1

and after a clear I get 'EVAP not ready' and 'CAT not ready' (not pictured)

Since it takes some running time for the O2 sensors and engine to get warmed-up, and a few start-stop cycles for the evap system to go through its test cycle, you will always get the "not ready" message after clearing the codes. This is to make sure people do not "cheat" on the emissions inspection by clearing the codes just before the emissions test.

Typically there is a P1000 code, but some scanners do not show the code, and give "not ready" messages for the specific emissions systems.

[flatlander]

@boywondergq1 - I have both the P0171 and P0174 codes too. I found that one of my CCV hoses was cracked too. I replaced them ($38 each from the local BMW dealer here in Illinois). I cleared the codes but they returned. I have some rough idle going on now.

[boywondergq1]

Well just to update everybody my CAT sensor eventually came to a 'READY' state but I'm still waiting on the 'EVAP NOT READY'. So I'm half way there.

I've gone through about a week's worth of everyday driving as well tried idling before and after my long trips for 5 mins or so, still no luck in getting this EVAP to go to a ready state. Not sure what else to try.

[mysweetx5]

A Code P0171/p0174 lean fuel condition can be caused by:
* Low fuel pressure due to a weak pump or leaky fuel 1. pressure regulator
. (use a fuel pressure gauge to check fuel pressure at idle)
* Dirty fuel injectors. (try cleaning the injectors)
* Vacuum leaks at the intake manifold, vacuum hose connections or throttle body
. (Use a vacuum gauge to check for low intake vacuum)
* Leaky EGR valve. (Check operation of EGR valve)
* Leaky PCV Valve or hose. (Check valve
and hose connections)
* Dirty or defective Mass Airflow Sensor (MAF). (Try cleaning the MAF sensor
wires or filament with aerosol electronics cleaner. Do NOT use anything else to clean the sensor, and do not touch the sensor wires)

[NJ04e53]

My X5 didn't trigger any codes, but I did get a rough idle at times and the whistling sound. I brought my car in supposedly for a CCV install but the indy mech found that my CCV is fairly new and the updated version. He however found that my intake lower MAF Intake elbow was cracked and that the DISA was broken. I asked him to go ahead and replace which cost me about $230 in parts (DISA and MAF tube) plus $50 in labor since I didn't have the time to do it myself. Overall, I feel that the car idles much better.

[boywondergq1]

So for those following my story, I should note that right after I replaced those two hoses and started it up the first time a puff of black smoke came out of the exhausts. I wonder what got in there after replacing the hoses to cause that, or if that incident messed up the O2 sensors.

My 'CAT not ready' finally went to 'ready'. So far so good. A few days later, 'EVAP not ready' finally came ready as well after about a tank of gas worth of driving for 2 weeks. Shortly thereafter, some new codes appeared:

P1158 and P1160: Fuel Trim Adaptation Additive Low (Bank 1) and (Bank 2) <-- (from what I've googled)

Does this mean the 2 oil separator hoses I replaced did something? I've read that the Fuel Trim Adaptation 'adusts itself' over time. Do I need more time? Do I clear these and wait again?

Hmm. Mass Air Flow sensor? Yeah, called BMW and they want $695 CAD for a new one. I haven't had much luck with cleaning these.

I think I'm ready to throw in the towel on this one.