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2005 BMW: miles the service engine soon light came on

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I have a 2005 BMW 325I. At what appears to be excatly 95,000.00 miles the service engine soon light came on. I purchased a code reader and found the following codes. P0174 and P0171. (Bank one too lean) (Bank two too lean). I inspected the car and found a cracked vacum hose leading from the oil seperator to the lower dip stick tube and I replaced it. I also removed and cleaned the MAF sensor with MAF cleaner. I removed the MAF body from car, sprayed, thet dry for an hour and then re installed. I cleared the codes and the car ran great for 3 days. My wife drove home last night and parked it in the garage. This morning it will not start at all.... cranks but will not fire. No check engine light present? Is it related and/or where do i start now to find the issue? I would like assistance through the resolution of this issue.

Hello and welcome to justanswer.


My name is XXXXX XXXXX it will be my pleasure to assist you today.


First thing to do is check the fuel pump fuse.


Other than that, the the two most common causes of a crank no start is either 1) a bad crank sensor or 2) no fuel delivery. It is very unlikely that this is related to the cracked hose you replaced.


I would see if the car will catch/fire using quick start. If it will not start with the quick start, then you have a bad crank sensor and therefore no spark, and you will need to replace the crank sensor.


If it does fire on the quick start, then you have a fuel delivery problem and you will need to check the pump for power. If there is power present and the pump is not running, then the pump is bad. If there is no power, it is likely the relay.


I hope that is helpful, please let me know if you have further questions, or if I can clarify anything for you.


It has been my pleasure to help today and I wish you the best of luck with your vehicle.


If satisfied with my assistance, please press the green ACCEPT button so that I may be credited for helping today. I am not credited or compensated whatsoever until you press the green ACCEPT button. .


Many thanks,






Edited by Steve on 12/14/2010 at 4:25 PM EST
Customer: replied 6 years ago.
Is it possible a faulty (failing) crank sensor threw the P0174 and P0171 codes last week and not the cracked hose?

No, those codes are definately from the cracked hose. 100%.


Please let me know if you have further questions. Please do not forget to press the green ACCEPT button as this is the only way I receive any credit for the assistance I have provided today.






Customer: replied 6 years ago.
I have not used this "Just Answer" site before. I wish to try whay you suggested and find the issue before payment. Is this the accepted practice? I will go check these item you suggested in about 30min.

Hello again


Typically answers are accepted at time of answer. You are free to ask additional questions in the future once you have accepted, without further charge. You can go and try it if you like and accept later, but it is very important that you do accept, as I receive nothing whatsoever until that button is pressed, and your deposit will remain in your justanswer account until you accept.


Thank you in advance for accepting and ensuring my compensation.




Edited by Steve on 12/14/2010 at 4:42 PM EST
Steve and 2 other BMW Specialists are ready to help you
Customer: replied 6 years ago.
I have more information. When i got home car still failed to start. I unplugged the MAF sensor and the car started right up. Plugged it back in with engine running and got a transmission malfunction light. Power cycled car twice and trans error went away. Car is starting repeatedly now. i scanned for codes and this is what i see. There are 2 pending codes that have not set the "check engine light yet" P0174 (bank 2 too lean) and P0171 (bank 1 too lean). Also of all the Monitors the "Catalyst Monitor" and the "Evap Sys" monitors are stating not ready. I have not cleared the codes in 3 days. These should be reporting ready by now correct. It also appears the codes P0174 and P0171 are going to return.
So the car now starts with the maf plugged in?
Customer: replied 6 years ago.
yes but got pending P0174 and P0171 codes in obdII reader.
Customer: replied 6 years ago.

i'm letting to cool to double check the fitting on replaced hose under the oil seperator. It does appear that unplugging the MAF made it start right up.


Sounds like you may have a bad maf then. It is pretty rare for a maf to cause a non start. The systems would not necessarily be in ready status after 3 days, no.
Customer: replied 6 years ago.

hose was still fitted tight. car is running now. I'm going back to work. Please reply with additional possible causes for the p0174 and p0171 codes. IT sounds like an vacum leak under the plastic intake manifold but it might be the sound of the air flowing throught the plastic intake. Can i inject smoke into the brake vacum booster hose to check for leaks? Or would i inject smoke into the intake with the MAF removed? Once again i have the freez frame data from the code if you want that.


The number one cause for those codes is an air leak like you just fixed with the replacement hose


After that would be a bad MAF or crankcase vent valve failure. To test the ccv remove the oil dipstick with the engine running. If there is a high vacuum holding the cap down, then the ccv is bad.




Customer: replied 6 years ago.

What is the actual part name for the ccv. Dealer says the car does not have one. Is it called a regulator of some sort or do you have a part number? With dip stick removed there is mild to medium amount of suction when removing the oil filler cap. Check engine light back on with same 2 codes. 1 set confirmed another set pending.

Part 1 below


"Pressure regulating valve"


part number 11617501566 or 11617533400 for cold climate version





Parts diagram

actually can I have the last 7 of your vin to verify



Customer: replied 6 years ago.
Should there be any suction on the cap with the dipstick removed? I'm going to inspect hoses 2,3,7,and 6. I replaced hose 4 in your diagram. Is this regulator a part that can be replaced without removing the intake manifold? Thank you for helping me with this through resolution. Vin(NJ88112)
Customer: replied 6 years ago.
Should there be any suction on the cap with the dipstick removed? I'm going to inspect hoses 2,3,7,and 6. I replaced hose 4 in your diagram. Is this regulator a part that can be replaced without removing the intake manifold? Thank you for helping me with this through resolution.

I just double checked. The numbers I provided were correct. Always best to verify based on vin.


Here is a link to the info on replacing the CCV: CLICK HERE The proper repair calls for the manifold to come off, but it is possible to manage without removing it.


There should be very little suction.


You are welcome for the assistance. You can always consider a bonus if satisfied.




Customer: replied 6 years ago.
Thats a deal, once we get the light to stay off. And the codes to stay away. Lol. The article you referanced says 2001-2003 325i?

It is the same engine, you also have the M54 engine.




Customer: replied 6 years ago.
i got all the parts and hoses out of the car none of the others were cracked although they are all brittle. I will source and re install it all tomorrow.
Ok let me know how it goes.
Customer: replied 6 years ago.
it's all done. fired right up. Vacum on the cap with dip stick out is the same amount. That seems like i just spent alot of time and money on a good part. I will drive it tomorrow but suspect light will be comming back. I was going to change the fuel filter but all i can find is a fuel pressure regulator. Does this also contain my filter or is their a filter some where else in the car. The regulator is under driver floor pan.

the filter and pressure regulator are one unit on your car, shown below.


If those codes come back, you need to look for another intake air leak or swap out the maf for a known good unit.






Parts diagram

Customer: replied 6 years ago.
i'll see what happens when she takes it to work tomorrow.
Let me know.
Customer: replied 6 years ago.

Update Ran great last night drove it 20 miles started and restared it 20 times. Parked in garage. First thing this morning it cranked... sputtered... died and now just cranks and will not start again. I unplugged the MAF which worked to start it yesterday but no luck today. It never actually started but has 3 codes already P0174, P0171 and a new P0333 " crankshaft position sensor" Could all codes be from an intermittent crank shaft sensor? The engine never started to develop a vacum leak? Is this the sensor on front of motor below passenger side radiator hose? does my car need the one with or without the wire pigtail hangigng off. I cannot even see the sesor but might be able to remove by touch. What should i need to remove to get to this for replacement. I'm just confused that potentially a "crankshaft sensor", " vacum leak" and "MAF" all failed at the same time?? Maybe this is all the crankshaft sensor?

Customer: replied 6 years ago.
I am going to buy the crankshaft sensor today. hopefully i can get it installed and test. Looks like this sensor only comes one way so ignore my pigtail question Thank you.

the crank sensor may be your no start issue. it is a very common cause of a crank no start


a crank sensor will not set lean codes. I would be shocked if replacing the crank sensor fixed those codes. The broken hose you initially replaced was causing a vacuum leak, which is a very common cause of lean codes. aside from such a leak, the ccv or maf would also cause lean codes.


crank sensor is 8 below



Parts diagram

Edited by Steve on 12/16/2010 at 7:25 PM EST
Customer: replied 6 years ago.
Will i need to remove the starter and throttle assembly to get to that or is it accesable? Any insight as to the fasted method of replacement would be helpful. Thank

Here is an outline: CLICK HERE




Customer: replied 6 years ago.
no problem
Customer: replied 6 years ago.
replaced crankcase angle sensor. No change. Cranks no start.

you will need to check for fuel and spark then.

Customer: replied 6 years ago.
starts with quick start spray and fuel pump fuse #54 is good.

Relay is behind the globe box, per this info: CLICK HERE


You can also check the pump, under the rear seat to see if it runs / has power: CLICK HERE



Edited by Steve on 12/17/2010 at 3:48 AM EST
Customer: replied 6 years ago.
Everything checked good all the way to fuel pump in tank. Pump not running while in pump assembly connected to the car harness (12v present at connector for prime cycle and crank). I removed the pump assembly then removed actual pump. I hooked pump straight to 12v power and it run's. I put back together and now it cycles then runs during crank. I feel like all the jostling around might have got the pump spinning again. An intermittent pump could have caused the lean code i'm sure. i'll try to source the pump tomorrow and reassemble back into the car.

let me know how it goes.


I would wager the original lean codes were from the broken vacuum tube...


Customer: replied 6 years ago.
i have gotten them (lean codes) 5 times since replacing the original vacum hose and 2 times again after replacing the ccv and all the other hoses? I agree the hose needed replaced but unless i have a bad fuel pump and additional vacum leaks then the pump was to blame. Once i replace the pump and pray it starts (Lol) i'll see if the lean codes still come back.I hate to think there might still be more wrong.
I have never come across lean codes from a pump, lets hope its the first time.
Customer: replied 6 years ago.
Steve. I installed a new fuel pimp friday night. Since that time we have driven the car everyday. No check engine light and it cranks every time. (no pending codes either) I beleive that this was the problem all along. I should also note that my wife had been noticing greater fuel economy. She got 465 miles from a single tank on her last trip to Lubbock. I feel like the fuel pump was under delivering and the car kept increasing fuel delivery till it finally hit the max 35% adjustment. Then it started throwing the "lean codes" until the pump failed completely. I think i must have craked that vacum line when i was removing it for inspection. It was brittle and needed replaced but since the lean codes only went away after a new fuel pump then the pump must have been the cause of the lean codes and then when it failed, also the crank no start.
Glad you got it sorted out. As I said I have never seen a fuel pump cause lean codes (they are almost always ccv, vacuum leak or maf) but there is a first time for everything. If you look back to my very first answer to your crank no start question, it was crank sensor or fuel pump. Please let me know if I can provide anything further. Please consider a bonus if satisfied with my assistance. Happy holidays. Steve

Edited by Steve on 12/21/2010 at 8:40 PM EST

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