Code P0171 - P0174

[djc4]

So I went to autozone to get my SES codes checked and I got these. I already had an idea but, if someone knows exactly which O2 Sensors these are that would be great. What I'll probably end up doing is just replacing all of them.

This is what the codes were:

P0171 - P0174

Lean Bank1 & Bank2

I figure I need to change the o2 sensors near the intake manifold and intake, possibly the MAF Sensor. Then also change the pre-cat o2 sensor and post-cat o2 sensor.

I hope this fixes my power issues. I really haven't been able to really enjoy this engine since it's been like this the past 3 months since I just bought it. The acceleration stops at about 4000 rpm in any gear because the sensors are bad and vanos and the engine in general, stops working.

Any help would be great guys. How much is this repair gonna cost? Is it a difficult DIY?

[Chet Vlaun]

When you get lean on both banks, it is likely due to intake air leakage. It is very unusual for both O2 sensors to fail at the same time.

Good luck

[thejlevie]

Unless the car has been fitted with an oiled air filter the MAF is not likely to be the problem and should be the last thing considered. The more likely candiates are aged pre-cat O2 sensors (useful life is 80-90kmi), intake leak, or failed CCV. Those are the areas to check first.

[e39dream]

a 540i car I was working on yesterday popped these codes.

If I had a leak in the secondary air system near the drivers side cylinder head would that throw these codes?

[e39dream]

anyone?

[ViolinARC]

Not sure about the cylinder head leak e39dream but I wanted to add that one only needs to replace the pre-cat O2's (if they've failed) as the post-cat O2's are only monitoring the exhaust output and really do not alter the performance settings (at least that's what I understand from my research). GL...

[e39dream]

Thanks dude- I'm pretty sure once I fix this exhaust tube properly and reset the light he should be good to go. I hope.

It only makes sense for the code to be related, 1 thing gave us trouble on the car, 1 emissions related set of codes comes up.

[plblevins]

This is the very first thread I've read and thanks nathans pic posts I found my leakage! Thanks bimmerforums!

[2000540it]

i have the same two codes in my 2000 540it and from everything i have read it could be any of a number of things here is my situation. 1st got only p0171 and then my dsc module went. replaced that and got car back driving again then replaced precat o2 sensors now getting SES light with codes being p0171 and p0174. car has 170k and do not want to parts chase. Dealer does not think is MAF because that would throw rich and lean codes??? Trying to save myself some headaches and any suggestions on what it could be and how to test would be extremely appreciated. The car seems to run and start fine. The only power loss i notice is under hard acceleration. Please help because i love this car and do not want to have to let it go.I have already checked (cautiously) for vac leaks with carb cleaner but am afraid it will harm plastic/rubber parts. I have also removed and inspected the intake boot/gaskets for cracks and found nothing. I pray that i do not have to do the labor intensive ccv replacement uuuughhh!!!

[2000540it]

ok so i am answering my own post.

after much stress i decided to parts chase.

i got lucky on this one. i replaced my maf for only $113. i ordered the bosch maf from GERMANAUTOPARTS.COM,vw part #06A906461A and removed the sensor itself from the housing. VW puts theirs on with a security key that is 5point not torx (i used pliers to get the screws out) the one in my 540 was torx(security). after the replacement on 1st start my car immediately stalled on 2nd start was looking for idle maybe 15 secs of fluctuation before it set itself. this diy was one of the easiest i have completed to date and the car that i thought was running fine proved me wrong....now its running fine. it is apparent to me now that i have a lack of experience with 540s my 528 that i have had for 4years has been my only basis for experience i now realize the pants crapping power of the 540 and am once again in the love of my love hate relationship with this car.and for anyone looking the security torx is available at advance autoparts for $8. i hope this helps anyone with similar issues.The bosch part number on the MAF was the same when removed from the housing. i also did my pre cat o2 sensors(before the lean codes came) and that did nothing for the codes although i have read it can be the cause of the prob. thanks to all for helping this shadetree machanic fix his baby..

[edwards]

Hi. I'm new here but genuinely appreciate the help.

My 330CI '04 threw the following codes.P0171B, P0174B, P0300B, and P0705.
The engine acts like it wants to cut out and it rattles. Does anyone have ideas as to what it could be?

Before the check engine light came on, I was told the rattling was my transmission. I just dropped 2K$ rebuilding it. I'm sure my displeasure is palpable.

M

[poppysc]

Came to the forum to find help with the same problem codes,P1071, P1074, on my wifes 2003 530I. I have a story to tell, and maybe it will help someone else. The codes would come and go and I tried several things before finding the real cause.My "adventures" cost me about $600 in parts. My son is a good mechanic and finally found the problem. Here is the order in which I approached the problem, starting with the cheapest parts first. Changed gas cap-$12, put in a can of Seafoam fuel system cleaner-$10, Changed fuel filter-$85, changed input O2 sensors-$150. Cleaned Mass air sensor with special cleaner-$12, finally bought new MAF sensor $260. While changing the MAF sensor my son found a big crack in the throttle intake elbow where it branches into a smaller line, About 30mm in diameter. Fixed it with some black silicone adhesive. I guess I can rationalize the cost of the new O2 sensors as the car has 130k on it and recommendations are to change at 100k. The rest I probably didn't need. Ouch! Told my wife the MAF is her christmas present. There are a couple of postings that recommend checking vacuum leaks first. I highly recommend it.

[edwinaso]

check the intake air hose... the one right next to the engine is usualy torn at the elbow "the Y plit" cost $18.00

[eflo]

i had these 2 codes. got new pre cats 02s. no difference. changed ccv. a little better. just got new maf on last week. problem solved!

[metro20]

Hello everyone.
I am new and appreciate to find very good advice and info in this forum. I had just changed out the Thermal stat the other day on my 2002 525i, ran for one day then appeared two more codes P0171-P074. Today, I decided to removed intake muffler, see link:
http://www.realoem.com/bmw/showparts.do?model=DT43&mospid=47584&btnr=13_0414& hg=13&fg=20
and Hot-film air mass meter, boots ..toward throttle housing, see link: http://www.realoem.com/bmw/showparts.do?model=DT43&mospid=47584&btnr=13_0919& hg=13&fg=15
Here I discovered the small size of Y ruber boot ripped open (item# 7). I did a temporarily quick-fix with Linerless Rubber Splicing Tape (3M Scotch, pn: 130C), applied two layers of tape to entire length of damage boot and used heat gun to melt it. The code is reset and the car now run a lot of better. I ordered a new boot for $14 from Europart America . http://europartsamerica.com/ssf/part_ number_search/13541437191 and will replace it when the part arrive. I hope this is it and will inform the outcome

[Mysweetx5]

[QUOTE=2000540it;15873271]ok so i am answering my own post.

after much stress i decided to parts chase.

i got lucky on this one. i replaced my maf for only $113. i ordered the bosch maf from GERMANAUTOPARTS.COM,vw part #06A906461A and removed the sensor itself from the housing. VW puts theirs on with a security key that is 5point not torx (i used pliers to get the screws out) the one in my 540 was torx(security). after the replacement on 1st start my car immediately stalled on 2nd start was looking for idle maybe 15 secs of fluctuation before it set itself. this diy was one of the easiest i have completed to date and the car that i thought was running fine proved me wrong....now its running fine. it is apparent to me now that i have a lack of experience with 540s my 528 that i have had for 4years has been my only basis for experience i now realize the pants crapping power of the 540 and am once again in the love of my love hate relationship with this car.and for anyone looking the security torx is available at advance autoparts for $8. i hope this helps anyone with similar issues.The bosch part number on the MAF was the same when removed from the housing. i also did my pre cat o2 sensors(before the lean codes came) and that did nothing for the codes although i have read it can be the cause of the prob. thanks to all for helping this shadetree machanic fix his baby..:

Well... this issue is commonly a (shot in the dark) because there are so many locations to look for when it comes to these two codes: P0171/P0174. I've read people comments on the forum stated that it could be from: O2 sensors, but unfortunately it is not. Oxygen sensors would likely threw out Instead: (P0130/1159/1143) which I've experienced in the past. After all I'm glad my friend that (you were lucky to step your foot on the right spot) which was the air mass sensor on your car. Unfortunately! I'm actually experiencing the same codes too: (P0171/P0174) on my: 01 BMW X5 4.4i E53/M62 engine type
I've cleaned the air mass sensor, but after a few driving around same codes came back again. If that is the same case for me, it would be great!!! but if not, imagine trowing:$245.17 for my Part number: 13 62 1 433 567 @ Germanautoparts.com and part don't resolve my issue.

[chrisspa]

Error Code P0174 on BMW 330Ci 2001 - After seven trips to BMW service, no results.... I started replacing all of the intake hoses and parts, etc..... No results.

Finally found a small boot covering an extra vaccum port not being used on the back side of the intake manifold (between engine and fire wall), boot was cracked and leaking.... replaced boot (a $3 part) and the P0174 code went away. Spent hundred at BMW service, plus replaced most of the vaccum system before finding the problem..

[windjimes]

Had both the P0171 & P0174 on my '01 740iL and thanks to those above and the fact that i have an '01 540iT for sale in my driveway was able to part-swap to find the issue.

Mine turned out to be the MAF.

But the MAF that was throwing the codes in the 740 is now in the 540 and NO codes... so i suspect the plug at the top of the MAF may have simply needed to be re-seated.

My suspicion comes from an issue i had with the 540 that i mistakenly traced to the LCM's mosfets and was about to get into all kinds of expensive strife when i noticed that after unplugging one of the headlights it then worked fine. I then unplugged, cleaned and reseated all the forward light plugs on the car and voila- no more LCM issue.

its sure nice to have my 740 back!

[1968volks]

I had similar codes that the banks were too lean, plus I had one that said "misfire at low fuel level". Before I spent a dime on chasing a hose leak or thinking it was the MAF, CCV, etc., I had a smoke test done for $40 at my local shop. They found a leak on the vent hose from the oil pan to the CCV. After the hose was changed, all the codes disappeared and my fuel mileage went back up! Usually when the O2 Sensor goes, you will get its specific code. Either way, the intake O2 should be changed at 100k.

[leeuga11]

Woke up this morning to a service engine light. Code po174. I'm about to look for leaks in the intake. Car is running great (so far). 01 530i. 70000 miles.

Just checked for leaks. Felt around and saw this very small hose which looks a little worn. I pushed on it some to make sure it was tight. Cranked car and light has turned off. Has anyone else had light come on and them turn off? Also I'm in ga and we had record lows last night. Wonder if that has anything to do w it. Any advice would b appreciated. Thanks

[jujulio]

i just change the pre cat o2 sensors and i still have the SES light on. im thinking now i should take the intake appart for a second look and replace all the hoses around it.wich i already replace that dreadful Y hose near the motor that always gets ripped. MAF next? or the after CAT sensors wich i already purshase but havent installed yet

[purplecty]

Came to the forum to find help with the same problem codes,P1071, P1074, on my wifes 2003 530I. I have a story to tell, and maybe it will help someone else. The codes would come and go and I tried several things before finding the real cause.My "adventures" cost me about $600 in parts. My son is a good mechanic and finally found the problem. Here is the order in which I approached the problem, starting with the cheapest parts first. Changed gas cap-$12, put in a can of Seafoam fuel system cleaner-$10, Changed fuel filter-$85, changed input O2 sensors-$150. Cleaned Mass air sensor with special cleaner-$12, finally bought new MAF sensor $260. While changing the MAF sensor my son found a big crack in the throttle intake elbow where it branches into a smaller line, About 30mm in diameter. Fixed it with some black silicone adhesive. I guess I can rationalize the cost of the new O2 sensors as the car has 130k on it and recommendations are to change at 100k. The rest I probably didn't need. Ouch! Told my wife the MAF is her christmas present. There are a couple of postings that recommend checking vacuum leaks first. I highly recommend it.

If youre still around. Do u have a pic of which hose was cracked?

[edjack]

These codes show both banks too lean. You have a vacuum leak in the intake tract, after the MAF. Suspects are torn intake boot, or throttle body-to-intake manufold gasket.

[530monkey]

I had the same issue on my 2001 530i 170K. I removed all of the boots and carefully inspected them (no problems), cleaned the MAF (looked clean already), and inspected every vacuum line visible. I took my code scanner with me and logged each time the CEL came on and the milage. I was sure that it was a vacuum leak. Wanting to solve the problem I decided that I needed smoke test the intact system. Unfortunately I don't have access to a smoke system. I decided to test the system with pressure. I removed the filter box and MAF. I attached a cover on the intake tube and inserted a pressure fitting. I applied about 5 - 10 lbs of air into the system while listening for leaks. I found 2. 1) the breather hose coming out of the valve cover was detached 2) the o Ring in the dip stick was venting air. I reattached the vent line and road tested the car. Instant improvement in idle and performance. I don't think that the dip stick o-Ring was impacting the vacuum. However, it was allowing oil to blow out of the pan and onto the bottom of the engine and chassis. Replacing the o ring is the next project. I have vacuum leaks !!! Thanks for everyone's input to the forum. Great resource for those of use who have the money to buy the car but aren't willing to shell out $1,000s on repairs.

[debbrumb]

My 02 325i E46 P0174 code comes on during certain fuel levels. Usually between full and 3/4 then goes off and comes back on close to half and then before empty and goes off when I fill it. Changed fuel filter and cleaned MAF with a can of spray from an auto parts store for $12. I don't understand how fuel levels effect it.