P0171 - System Too Lean (Bank 1)
NEWS
 

+ Reply to Thread
Results 1 to 30 of 30
  1. #1
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180

    P0171 - System Too Lean (Bank 1)

    Ok, my "new" Passat (2002 B5 1.8T - 41,000 miles) is starting to give me a headache.

    I did my first service (air filter, plugs, M1 Synthetic 0-40 oil, & filter) to it about 3 weeks ago (BTW-Thanks for all the helpful info on how to do it and what to use). Friday evening my CEL (Check Engine Light) comes on while driving to dinner.

    Saturday morning, after reading up about what it could be in the forums, I took it over to my local Advance Auto Parts (like an AutoZone) store and they pull a P0171 code on it and they tell me it's probably the O2 sensor. They guy reset it for me and said if it comes back on then I should come back and buy one. The light was out the rest of Saturday and Sudnay but of course on my way to work yesterday it comes back on again. I went to the parts store again and it's the same code. The girl that worked there didn't know squat and the other guy there said it could be anythign and suggested taking it to the dealer or a mechanic.

    From what I have read, I think I should;

    1) start with cleaning the MAFS (can you tell me exactly what cleaner to use?)

    MAFS cleaning (multiple pictures)

    and if that doesn't clear it then,

    2) replace the 4 vacuum hoses (they looked fine to me)

    HELP with VAG code!!!

    and if that doesn't fix it then,

    3) replace the O2 sensor?

    http://www.passatworld.com/forums/sh...74&postcount=1


    Does this sound like a good plan of action or should I just take it to the dealer (under warranty) or a mechanic?




    I bought this car becasue I thought it was going to be reliable....

    P.S. I have slowly noticed a decline in gas mileage too.

  2. Remove Advertisements
    VW Passat Forum
    Advertisements
     

  3. #2
    2nd Gear
    Join Date
    Oct 2005
    Location
    Miami, Fl.
    Age
    37
    Posts
    816
    if you have a warranty, take it to the dealer and have them deal with it. How long have you had the car?

  4. #3
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by jestic
    if you have a warranty, take it to the dealer and have them deal with it. How long have you had the car?
    Thanks! I think I will see if I can drop it off there Friday even though my wife thinks I can do it myself. I have no clue how to work on it because it's my first one. (even though most of it looks simple enough)

    I bought towards the end of October 2005 with 34,700 miles on it and I have almost put 7,000 on it already. I use it to drive to work every day (67 mi.) and was hpoing ti would get at least 30 mpg and be reliable.
    At least it still runs, right?

  5. #4
    2nd Gear
    Join Date
    Oct 2005
    Location
    Miami, Fl.
    Age
    37
    Posts
    816
    its better to air on the side of caution. God forbide you do something wrong while your doing an easy fix and then the stealership blames it on you. That would suck.

  6. #5
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by jestic
    its better to air on the side of caution. God forbide you do something wrong while your doing an easy fix and then the stealership blames it on you. That would suck.
    Yeah, I heard that. That's why I decided to use the Mobile 1 Synthetic 0-40 "approved" oil in it too. I was going to use this other high mileage stuff by Mobile 1 that was supposed to be good for something like 7500 miles, since I drive so many miles every day but I figured I would rather be safe than sorry. Who knows what the previous owner used because there are no records so it might void the warranty anyway.

  7. #6
    4th Gear
    Join Date
    Apr 2001
    Location
    Northbridge, MA
    Posts
    3,341
    The MAF has a 7/70 extended warranty, not sure if it covers second owners though. They also offer aremanufactured sensor for less than $100 should it be out of warranty.

    O2 sensors "typically" don't start acting up untill higher mileage. But YMMV.

    If you can find a vagcom you can log the MAF readings and/or monitor the O2 sensor. Either issue will potentially mess up the fuel economy and set a CEL.

  8. #7
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by scotty_passat
    The MAF has a 7/70 extended warranty, not sure if it covers second owners though. They also offer aremanufactured sensor for less than $100 should it be out of warranty.

    O2 sensors "typically" don't start acting up untill higher mileage. But YMMV.

    If you can find a vagcom you can log the MAF readings and/or monitor the O2 sensor. Either issue will potentially mess up the fuel economy and set a CEL.
    Thanks! I will have to call the dealer and see if it would be covered or not (assuming that's the problem). Do you think it's worth trying to clean first?

    I think that's their typical answer to the P0171 problem code, "you need a new O2 sensor. It's about $150 and I can have it here in 2 days.".

    Interesting! The VAG-COM is not the same as these basic OBD II testers right? It's the kind that hooks up to a laptop or something with some detailed sofware for VW's, right?

  9. #8
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by colorick
    Thanks! I will have to call the dealer and see if it would be covered or not (assuming that's the problem). Do you think it's worth trying to clean first?

    I think that's their typical answer to the P0171 problem code, "you need a new O2 sensor. It's about $150 and I can have it here in 2 days.".

    Interesting! The VAG-COM is not the same as these basic OBD II testers right? It's the kind that hooks up to a laptop or something with some detailed sofware for VW's, right?
    I forgot to ask if the DV could be causing the problem.

  10. #9
    4th Gear
    Join Date
    Apr 2001
    Location
    Northbridge, MA
    Posts
    3,341
    probably not.

    as you recently serviced the air filter, you might want to make sure you didn't break a vac line or electrical connection near the airbox.

  11. #10
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by scotty_passat
    probably not.

    as you recently serviced the air filter, you might want to make sure you didn't break a vac line or electrical connection near the airbox.
    ok thanks.

    Yeha, anything is posssible I guess. I tried to be careful when I did it and I looked at the lines and the connections again Saturday but when it's your first time you never know what you could be accidentally doing wrong until it's too late.

  12. #11
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by scotty_passat
    probably not.

    as you recently serviced the air filter, you might want to make sure you didn't break a vac line or electrical connection near the airbox.
    ok thanks.

    Yeah, anything is posssible I guess. I tried to be careful when I did it and I looked at the lines and the connections again Saturday but when it's your first time you never know what you could be accidentally doing wrong until it's too late.

  13. #12
    4th Gear
    Join Date
    Apr 2001
    Location
    Northbridge, MA
    Posts
    3,341
    you can view the MAF reading with just about any decent OBD-2 scanner/software. Here is another tool I use for non-VWs: http://www.obd-2.com

    Although VAGCOM is the *best* tool for this application, I highly recommend purchasing it if you plan to keep and servie the car yourself for a long time, the dealer charges typically 1 hour labor to scan the car so after a couple of CELs the tool is "paid for".

  14. #13
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by scotty_passat
    you can view the MAF reading with just about any decent OBD-2 scanner/software. Here is another tool I use for non-VWs: http://www.obd-2.com

    Although VAGCOM is the *best* tool for this application, I highly recommend purchasing it if you plan to keep and servie the car yourself for a long time, the dealer charges typically 1 hour labor to scan the car so after a couple of CELs the tool is "paid for".
    Cool! Thanks for the link.

    I like how you think! Any good links for an affordable VAG-COM?


  15. #14
    the deal finder!
    Join Date
    Feb 2004
    Location
    LA, CA
    Posts
    15,564
    hoses would be the easiest, so do that first.

    vag-com cable is ~$40 from ebay, but check the ross-tech website for the restrictions on the shareware version.

  16. #15
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by D.Passat00
    hoses would be the easiest, so do that first.

    vag-com cable is ~$40 from ebay, but check the ross-tech website for the restrictions on the shareware version.
    Ok, thanks! I thought the hoses were a little tougher and more time consuming than cleaning the MAF but maybe I'll do em' both at the same time. (any suggestions for the type of cleaner?)

    So you are saying I can buy a VAG-COM cable and then get the software from ross-tech and use my current computer? I wish I had an extra computer or lap top I could use but might have to do a temp relocate of mine (upstairs) or get a new lap top.

    Also, is it ok to still drive it the way it is?

  17. #16
    3rd Gear
    Join Date
    May 2000
    Location
    Tempe Arizona USA
    Posts
    2,396
    Quote Originally Posted by D.Passat00
    hoses would be the easiest, so do that first.
    The OEM vacuum hose is known to be problematic, so I would take a look at them first. One of the most common trouble spots is the vacuum line that connects to the front of the intake manifold. It was the first to go on my '98 and my friend's '01.

    -Mark

  18. #17
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by mghunt
    The OEM vacuum hose is known to be problematic, so I would take a look at them first. One of the most common trouble spots is the vacuum line that connects to the front of the intake manifold. It was the first to go on my '98 and my friend's '01.

    -Mark
    Cool, thanks for your input. I am going to go get some new vacuum line and cleaner on my way home after work. I just hope it works!

  19. #18
    the deal finder!
    Join Date
    Feb 2004
    Location
    LA, CA
    Posts
    15,564
    Quote Originally Posted by colorick
    Ok, thanks! I thought the hoses were a little tougher and more time consuming than cleaning the MAF but maybe I'll do em' both at the same time. (any suggestions for the type of cleaner?)

    So you are saying I can buy a VAG-COM cable and then get the software from ross-tech and use my current computer? I wish I had an extra computer or lap top I could use but might have to do a temp relocate of mine (upstairs) or get a new lap top.

    Also, is it ok to still drive it the way it is?
    well, the hoses might take a little longer, but it's cheaper than replacing the MAF. you can use the shareware version of vag-com, but it is limited. check out their website for details.

    http://www.ross-tech.com

  20. #19
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by D.Passat00
    well, the hoses might take a little longer, but it's cheaper than replacing the MAF. you can use the shareware version of vag-com, but it is limited. check out their website for details.

    http://www.ross-tech.com
    True, true, very true. I was just going to try to clean it first to see if that fixes it. Will the CEL turn off if it does or do I have to have it reset with the OBDII tool?

    I will, thanks!

  21. #20
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180

    Good news!

    Ok, I took it to Josh in my hometown, whom I found from the VAG-COM Locator list, http://www.steve-hall.com/cgi-bin/VAG-Locator.pl and we pulled a similar code on it;

    17544-Fuel Trim(Bank 1)/P1136-001 System Too Lean

    Josh thought it would either be a vacuum line (like EVERYONE has been saying) or a fuel pressure regulator. I decided to stop by the parts store to get some new vacuum line to replace the ones I have now to be safe. The guys there were kinda dumb and didn't know what 3.5mm hose was in American Standard Measure. I borrowed a flashlight to go look at mine to compare sizes and for some reason I happened to notice a different color in the elbow of a vacuum line near the rear corner of the Intake Manifold (under the Coolant Reservoir tank). After really looking at it closer and touching it I noticed that it had a crack in it. My heart was filled with joy because I knew that it had to be the source of all of my problems. I decided to pass on the part store hoses and go home and do a temporary electrical tape patching job on it.

    You can see the elbow in this picture

    (Picture was borrowed and edited from Vacuum Leak - Broken L Hose)

    Luckily Josh's VAG-COM reset my CEL so it wasn't on anymore. This morning on my way to work I noticed the car was running much better, better gas mileage, and I didn't hear as much "air noise" under the hood. Still no CEL up to now and am hopeful that it won't come back on again.

    I am ordering the new silicone lines today to be safe and am going to try to find out where I can find the replacement vacuum line with the elbow today, as well as how to replace it from here.

    Total cost for fix = $appx. 12" of electrical tape (of course I am still going to replace it)

    Thanks again!



    On a side note, this was a really sad story to read about this morning.
    http://www.comcast.net/news/index.js...04/296407.html

    I think they took way too long to try to get to them and I think they should have been more prepared for something like that (ie. more air available for them)
    Last edited by colorick; 01-04-2006 at 06:56 AM.

  22. #21
    the deal finder!
    Join Date
    Feb 2004
    Location
    LA, CA
    Posts
    15,564
    glad you got it fixed! that's a very common problem also.

  23. #22
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by D.Passat00
    glad you got it fixed! that's a very common problem also.
    Thanks, me too! Definitely nice to know it's nothing major or complicated.

    Can you share any info that you might have in regards to where to get the hose or a part #?

  24. #23
    the deal finder!
    Join Date
    Feb 2004
    Location
    LA, CA
    Posts
    15,564
    Quote Originally Posted by colorick
    Thanks, me too! Definitely nice to know it's nothing major or complicated.

    Can you share any info that you might have in regards to where to get the hose or a part #?
    should be # 06B 133 783 BC

    from this thread:

    Vacuum Hoses + Club B5 Picture Links

    i'd just buy it from the dealer, as it's ~$10 , but if you wanna buy it online, try www.1stvwparts.com

  25. #24
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by D.Passat00
    should be # 06B 133 783 BC

    from this thread:

    Vacuum Hoses + Club B5 Picture Links

    i'd just buy it from the dealer, as it's ~$10 , but if you wanna buy it online, try www.1stvwparts.com
    Excellent! Thanks for the thread. I wish I had found that one earlier. They had the exact same problem and a picture of the same hose and elbow as mine.

    I ordered the hose (06B 133 783 BC) and the clamps (N 102 582 01-intake manifold side & N 102 019 01-suction pump side) from 1stvwparts.com for a whopping $11.52 (plus S&H). Also I ordered 8' of the pretty blue vacuum line from hightempsilicone.com for $10 (plus S&H) which is not bad at all. What clamps do I need ofr the 3.5 mm hose & where can I get them? I hope it's easy to replace all of them.

    Thanks again for all of your help and information. Still no CEL as of this morning

    You guys have already saved me from spending unnecessary $$ and many headaches and I just got barely got my in October.

    Have one on me...
    Last edited by colorick; 01-05-2006 at 06:54 AM.

  26. #25
    the deal finder!
    Join Date
    Feb 2004
    Location
    LA, CA
    Posts
    15,564
    i believe the stock clamps are the one time use clamps which are a PITA to take off. you can get worm clamps from autozone or what not that should work too, and are easier in case you need to replace it next tim

  27. #26
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by D.Passat00
    i believe the stock clamps are the one time use clamps which are a PITA to take off. you can get worm clamps from autozone or what not that should work too, and are easier in case you need to replace it next tim
    ok thanks! Good point!

    I cancelled my order with 1stvwparts.com and found the hose at a local dealer for $13. I'm going to stop by on my way home and pick it up.

    Thanks again!
    Last edited by colorick; 01-05-2006 at 10:08 AM.

  28. #27
    4th Gear
    Join Date
    Oct 2004
    Location
    Encinitas CA
    Posts
    4,501
    Quote Originally Posted by colorick
    ... Also I ordered 8' of the pretty blue vacuum line from hightempsilicone.com for $10 (plus S&H) which is not bad at all. What clamps do I need for the 3.5 mm hose & where can I get them?
    I used the smallest screw worm-drive clamps I could find at AZO. They are a bit larger than optimal, but they seem to do the job.

    Quote Originally Posted by colorick
    I hope it's easy to replace all of them.
    Some yes, some no.

  29. #28
    1st Gear
    Join Date
    Nov 2005
    Location
    Loveland, Colorado
    Posts
    180
    Quote Originally Posted by John_E
    I used the smallest screw worm-drive clamps I could find at AZO. They are a bit larger than optimal, but they seem to do the job.

    Some yes, some no.
    Cool thanks! I bought a 4-pack at Autozone and they worked just fine. I think it took me a total of 3 minutes to do it. What a nice easy fix for a small amount of $. The dealer's replacement hose was definitely a lot thicker than the original.

    Unfortunately I think you are right based on what I have read there a a few tough places to get to. I will deal with it though.

  30. #29
    Neutral
    Join Date
    Sep 2007
    Posts
    3

    df

    df

  31. #30
    2nd Gear
    Join Date
    Oct 2005
    Location
    near you :D
    Age
    29
    Posts
    972
    it could also be the air filter that you put in causing the code, if there was excessive oil in the filter, the MAF sensor would be covered with oil.... try to clean the MAF with some MAF cleaner from the auto store.

  32. Remove Advertisements
    VW Passat Forum
    Advertisements
     

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Tags for this Thread

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
Powered by vBadvanced CMPS v4.1.2