Close

Results 1 to 17 of 17
  1. #1
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0


    1 out of 1 members liked this post. Yes Reputation No

    On my way to the track, but.....

    Hey guys,

    FML..I've been waiting for three weeks to get a chance to go to the track finally ready and have a full container of MS109 ready to go and bam! SES light.

    Need a bit of help on the code (P2C31 - Bank 1 Oxygen sensor before catalytic, trim control - Exhaust gas after cat conv.), I've searched around and found some old posts on the other forums with no resolution and a recent one e90 where the guy has replaced Pre cat O2 sensors and all injectors but still has the issue. I pm'd the guy to see if he resolved the issue but he won't get back to me.

    I first got the code about 300km's ago reset (through CobbAP) and I was fine, but now it comes back right away. I have DISv57 and ran a diagnostic but the code is 'not selectable or deletable' first time I've seen this. It wont let or give me the ability to run a test schedule to dig into the error.

    Any thoughts?? I keep the car in good mechanical condition new injectors, coils, plugs approx 1yr ago.

    Mods (all done ~1 1/2 yrs ago)

    MS catless downpipes
    AMS Intercooler
    Cobb stg 2+ Agr ST
    BMS Dual Cone Intake

    Click here to enlarge

  2. #2
    Join Date
    Nov 2009
    Location
    Simi Valley, CA
    Posts
    8,216
    Rep Points
    9,346.1
    Mentioned
    654 Post(s)
    Rep Power
    94


    Yes Reputation No
    Leaving a wired in DPFIX long term can cause that issue. As can a failing rear sensor.
    Burger Motorsports
    Home of the Worlds fastest N20s, N54s, N55s, N63s, S55s, and S63s!

    It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please see http://www.burgertuning.com/emissions_info.html for more information on legal requirements related to use of BMS parts.

  3. #3
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    Thanks for the quick reply Terry. I've never had the had the DPFIX and my JB4G5 is removed at the moment so I guess it's the rear sensor.

    Any idea why the error says Oxygen sensor pre cat? the other guy mentioned replacing the pre-cats sensors and still had the issue so the rears makes sense. The code seems ambiguous.

  4. #4
    Join Date
    Nov 2009
    Location
    Simi Valley, CA
    Posts
    8,216
    Rep Points
    9,346.1
    Mentioned
    654 Post(s)
    Rep Power
    94


    Yes Reputation No
    It could also be a precat sensor. Difficult to tell with trim errors as it's basically the DME telling you something isn't adding up with its reading.
    Burger Motorsports
    Home of the Worlds fastest N20s, N54s, N55s, N63s, S55s, and S63s!

    It is the sole responsibility of the purchaser and installer of any BMS part to employ the correct installation techniques required to ensure the proper operation of BMS parts, and BMS disclaims any and all liability for any part failure due to improper installation or use. It is the sole responsibility of the customer to verify that the use of their vehicle and items purchased comply with federal, state and local regulations. BMS claims no legal federal, state or local certification concerning pollution controlled motor vehicles or mandated emissions requirements. BMS products labeled for use only in competition racing vehicles may only be used on competition racing vehicles operated exclusively on a closed course in conjunction with a sanctioned racing event, in accordance with all federal and state laws, and may never be operated on public roads/highways. Please see http://www.burgertuning.com/emissions_info.html for more information on legal requirements related to use of BMS parts.

  5. #5
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    Gotcha, well I have a set of OEM pre-cat sensors on hand so I might as well try that first.

  6. #6
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    No Dice on swapping out the two front O2 sensors error code is still present and trims on Bank 1 are wonky.

    Rear O2 sensors are on the way hopefully this fixes the issue.

  7. #7
    Join Date
    Jan 2010
    Location
    SoCal
    Posts
    120,267
    Rep Points
    32,722.2
    Mentioned
    2131 Post(s)
    Rep Power
    328


    Yes Reputation No
    Click here to enlarge Originally Posted by bv1 Click here to enlarge
    Rear O2 sensors are on the way hopefully this fixes the issue.
    Please report when you get them.
    Chrome Space Bar Issue: http://www.boostaddict.com/showthrea...338#post738338


    Stage 2 or 2.5 E9X M3 S65 V8 supercharger kit for sale
    : http://www.boostaddict.com/showthrea...r-kit-for-sale

  8. #8
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    No dice, replace post cat o2 sensors still getting code and trims on bank 1 are still biased to the positive side.

    Going to pull plugs on bank1, maybe there is an injector going? and recommendations on what I should look at?

  9. #9
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    Click here to enlarge

    plugs look fine to me, no aha moment

  10. #10
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    Reset Lambda probes and lambda control within INPA trims seem to be good for now and code has not come back yet.

    Not sure that this is a permanent fix or if I bought myself time until the adaptation tables start to fill up again.

    Ran the some of the diagnostics within INPA and found the screen posted below to be interesting.

    All 3 lambda probes read a resistance of 256ohm except for Lambda after catalytic bank 1, which is the one giving me issues. I would think if something were wrong in the harness I would get a different error code though??

    I'll need to run a continuity check just in case I guess.
    Attached Images Attached Images  

  11. #11
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    Bump for help....

    Below is a chart of AFR from last night Bank 1 against Bank 2. Still no codes but obviously something isn't correct.

    Are post cat O2 sensors much involved in fuel trims?
    Attached Images Attached Images  

  12. #12
    Join Date
    Sep 2012
    Location
    Harrisburg
    Posts
    1,281
    Rep Points
    1,556.3
    Mentioned
    43 Post(s)
    Rep Power
    16


    Yes Reputation No
    There should be another page in INPA that shows the actual voltages the DME is reading from the sensors. Maybe "analog values 2" or something like that? Might want to check that out while the car is cruising on the highway. Maybe make a video or something so you can review it when you are stopped.
    Eppur si muove.

  13. #13
    Join Date
    May 2012
    Location
    Jacksonville, FL
    Posts
    2,971
    Rep Points
    2,932.4
    Mentioned
    78 Post(s)
    Rep Power
    30


    Yes Reputation No
    Click here to enlarge Originally Posted by bv1 Click here to enlarge
    Bump for help....

    Below is a chart of AFR from last night Bank 1 against Bank 2. Still no codes but obviously something isn't correct.

    Are post cat O2 sensors much involved in fuel trims?
    Post cat 02 sensors are used to calibrate the wideband 02's during stoich operation. When i last installed my downpipes, i crossed the rear 02's - this resulted in strange fuel trims and fueling issues until i fixed it. If a rear 02 goes, it will definitely cause some funky things to happen.
    2011 E90 M3 \ Melbourne Rot Metallic

    Click here to enlarge

  14. #14
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    Thanks man, yeah I couldn't find the screen for post cat o2 sensor voltage pre cat is there but no luck on post cat. I've seen the screen for other cars but not for the e90. Maybe I missed it I'll check again.
    Hopefully I can find the voltage measure on the post cats and that should pinpoint the problem.

    I do find it strange there is no resistance in INPA showing against the one sensor. Do you know if the resistance is against the heater or the sensor itself? But I would think if there was something wrong circuit or wiring wise I would get another different type of code.

  15. #15
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    Click here to enlarge Originally Posted by lulz_m3 Click here to enlarge
    Post cat 02 sensors are used to calibrate the wideband 02's during stoich operation. When i last installed my downpipes, i crossed the rear 02's - this resulted in strange fuel trims and fueling issues until i fixed it. If a rear 02 goes, it will definitely cause some funky things to happen.
    Good to know, thanks. I've read it varies and on some platforms the post cat O2's are mainly monitoring efficiency of the cats and not that involved trim wise.

  16. #16
    Join Date
    Sep 2012
    Location
    Harrisburg
    Posts
    1,281
    Rep Points
    1,556.3
    Mentioned
    43 Post(s)
    Rep Power
    16


    Yes Reputation No
    I don't know what that resistance is representing, but I bet it is not a real resistance value at all. First, the numbers are exactly the same for three of the sensors. When measuring anything real, you expect a certain amount of variation from one unit to the next. If those numbers represent a real resistance, there is less that 0.4% variation between them. That sounds fishy especially considering not all of the sensors are the same type. Second, 256 is a significant value in computers because it is the number of unique values 8 bits can represent. So I think this value is not a real resistance reading and needs interpreted a different way.

    The heater would have a far lower resistance than 256 ohms. I would expect 10 or 20 ohms. The sensor itself outputs a voltage, so you would never read the resistance of the senors to take a reading.

    That reading may mean there is a wiring fault somewhere, but that is why I am curious to know what the DME is reporting as the voltage read from the sensor. It is definitely odd all the sensors read 256 except that one.

    The reason it is thought the rear sensors are used to calibrate the front sensors (besides anecdotal evidence), is because the front sensors are wideband sensors, and need calibrated periodically.

    http://www.innovatemotorsports.com/r...ycalibrate.php

    I believe the N54 primary sensors are Bosch sensors.
    Eppur si muove.

  17. #17
    Join Date
    Oct 2011
    Location
    Toronto, Canada
    Posts
    59
    Rep Points
    63.4
    Mentioned
    1 Post(s)
    Rep Power
    0



    Yes Reputation No
    Appreciate the help, makes sense. The resistance being that close does seem a little hard to believe good point.

Tags for this Thread

Bookmarks

Posting Permissions

  • You may not post new threads
  • You may post replies
  • You may not post attachments
  • You may not edit your posts
  •