2006 BRM Limp Mode Diagnostic Help (w/ VCDS charts)

Discussion in 'Mk5 VW Jetta, Sportwagen, and Audi A3 TDI forum' started by SWXXIV, Dec 15, 2016.

  1. SWXXIV

    SWXXIV New Member

    Joined:
    Mar 26, 2015
    Messages:
    3
    Car:
    2006 VW Jetta BRM 5-speed
    Location:
    Colorado Springs, CO
    Hi Folks,

    Thanks in advance for your help. I'm new to diagnosing these types of issues and I'm also just learning how to use VCDS for diagnostics.

    I'm getting some limp mode issues on my 06 Jetta BRM with 260,000 miles. I did the timing belt and camshaft myself in May (and new fuel filter), and drove it from Fairbanks to the Olympic Peninsula in October with no issues.

    Three weeks ago, after having limp mode occasionally, I threw a P0299 code going up a long hill (it didn't normally throw a code, this was novel). I reset it at autozone, then a few days later got it again (P0299). Always underboost. I borrowed a vacuum hose to make sure my turbo actuator wasn't bad. The VNT actuator holds pressure and moves when it should via hand pump.

    I got a VCDS cable last week and I'm finally starting to play with it now. I'm trying to do as much as possible with it before undertaking anything that requires tools and space (which I don't have at my current apartment). That means I haven't done a comprehensive boost leak or vacuum leak test.

    Initial DTC scan can be seen under "Log File Initial". That's the auto-scan log straight from VCDS, all controllers. The only engine-specific code is the underboost condition. Note: I have retarded timing of about -2.9, per this method, which I intend to fix. I used the timing belt tools for the replacement in May but until I had VCDS I couldn't see that my timing was a hair off. It's been driven about 4,000 miles like this.

    I then took a trip around the block and logged the MAP (actual) and MAP (specified). I'm getting basically no boost at the MAP, as can be seen in the file "Inital boost graphic v2.png".

    Then I unplugged the MAF and got better boost response, as seen in "Boost, no MAF.png". Still not stellar. The traces aren't moving in lockstep, and the MAP (actual) takes a while to build. I then plugged the MAF back in, cleared the CEL, and ran the test again to make sure it was the MAF that changed it and not other factor I wasn't controlling. Sure enough, with the MAF plugged in, it went back to having hardly any boost. This makes me feel like the MAF could be involved, but I don't know if this alone is the smoking gun or just one factor. For example, what if there is some other restriction in the intake preventing high flow?

    To further test the MAF I tried to chart the MAF specified vs MAF actual but I can't find the "MAF specified" anywhere in the Measuring Blocks. I found the MAF actual no problem. It graphs against EGR on block 03. See "MAF v RPM" for the MAF specifically, and "EGR" for the EGR specified, EGR actual, and RPM data all logged as a time-series. The MAF never pulls more than 800 mg/ str, even at almost 4000 rpm. The EGR specified seems to deviate a lot from the actual, and the actual has a strong correlation with RPMs at times. Is that normal?

    The RPMs are high upon startup (around 950) and then settle to 800 within a few minutes of driving, but before the car gets up to operating temp. I've read that this can be caused by leaks.

    What other data can I collect before I invest in tools to do a boost or vacuum leak check? I just dropped $350 on a cable and I want to use it!

    Thanks again for your time and help.

    -SWXXIV
     

    Attached Files:

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  2. Keithuk

    Keithuk Super Moderator

    Joined:
    Aug 29, 2010
    Messages:
    6,908
    Car:
    2010 Golf GTD (170) CBBB
    Location:
    Stoke on Trent, England
    http://wiki.ross-tech.com/wiki/index.php/16683/P0299/000665
    http://wiki.ross-tech.com/wiki/index.php/01331
    http://wiki.ross-tech.com/wiki/index.php/00003
    http://wiki.ross-tech.com/wiki/index.php/01331
    http://wiki.ross-tech.com/wiki/index.php/00470
    http://wiki.ross-tech.com/wiki/index.php/00932
    http://wiki.ross-tech.com/wiki/index.php/01331
    http://wiki.ross-tech.com/wiki/index.php/00930
    http://wiki.ross-tech.com/wiki/index.php/00870
    http://wiki.ross-tech.com/wiki/index.php/00361

    VAG Error Code: 01505


    Fault Location:
    Indicator Bulb: Rear Right (M8) - Electrical Fault in Circuit/Open Circuit/Short Circuit to Earth/Positive

    Possible Cause:
    Indicator Bulb: Rear Right (M8) does not illuminate.

    Fuse(s).
    Wiring/Connector(s).
    Failed or incorrect bulb installed.

    Possible Solutions:
    Check/Replace Fuse(s).
    Check/Replace all faulty Wiring/Connector(s).
    Verify correct light bulbs are installed.
    Test wiring harness, see factory repair manual.

    VAG Error Code: 02788


    Fault Location:

    Internal Communications Error - Intermittent

    Possible Cause:
    Fuse(s).
    Wiring/Connector(s).

    Possible Solutions:
    Check/Replace Fuse(s).
    Check/Replace all faulty Wiring/Connector(s).
    Read Measuring Value Blocks (MVB).

    I have this one 00109 on mine but I will make a new thread about this.

    VAG Error Code: 00109


    Fault Location:
    Turn Signal Lamp: Driver, Left Mirror (L131) - Electrical Fault in Circuit

    Possible Cause:
    Wiring/Connector(s).
    Voltage Supply for Left Mirror, Driver, Turn Signal Lamp (L131) faulty.
    Left Mirror, Driver, Turn Signal Lamp (L131) faulty.

    Possible Solutions:
    Check/Replace all faulty Wiring/Connector(s).
    Check Voltage Supply for Left Mirror, Driver, Turn Signal Lamp (L131).
    Check Left Mirror, Driver, Turn Signal Lamp (L131) Operation.
     
  3. DePe

    DePe New Member

    Joined:
    Jan 11, 2016
    Messages:
    7
    Car:
    Volkswagen Jetta 2006
    Location:
    Chicago
    Mods:
    Kerma TDI Cam and tuning
     
  4. DePe

    DePe New Member

    Joined:
    Jan 11, 2016
    Messages:
    7
    Car:
    Volkswagen Jetta 2006
    Location:
    Chicago
    Mods:
    Kerma TDI Cam and tuning
    Did you ever figure out why you were underboost? Im having my check engine come on and my mechanic says the turbo charger is under boost and i go into limp mode sometimes on the highway and then sometimes not, i don't know what it may be, he says now it may be electrical. Do you have any thoughts on it, or has anyone else experienced it, thank you
     
  5. SWXXIV

    SWXXIV New Member

    Joined:
    Mar 26, 2015
    Messages:
    3
    Car:
    2006 VW Jetta BRM 5-speed
    Location:
    Colorado Springs, CO
    DePe,

    If you haven't read it yet, check out this link: http://www.myturbodiesel.com/wiki/l...roubleshooting-vw-seat-skoda-audi-tdi-engine/
    And this one: http://www.myturbodiesel.com/wiki/maf-sensor-faq-troubleshooting-replacement-vw-audi-tdi-diesel/

    I didn't get much further because my car is parked near the Seattle airport for the holidays. However, I can tell you that my car stopped tripping into limp mode when I pulled the MAF sensor connector. I was able to drive all the way to Seattle without tripping it, which was impossible over the Thanksgiving holiday. You can see above that my boost improves dramatically with the MAF disconnected. My car almost certainly has a bad MAF, especially since I'd had a K&N filter in it for a few years (mea culpa).

    If you dont have VCDS, go ahead and unplug the MAF sensor and try to get it to go into limp mode. Generally, low RPMs at full throttle on a hill with trip it. Interstate on ramps are great for that sort of thing. Also, see if you can tell a difference in acceleration between when it's plugged in vs not. My car actually pulls harder without a MAF.

    Good luck. Let us know how it goes!

    -SWXXIV
     
  6. DePe

    DePe New Member

    Joined:
    Jan 11, 2016
    Messages:
    7
    Car:
    Volkswagen Jetta 2006
    Location:
    Chicago
    Mods:
    Kerma TDI Cam and tuning
    The first article i read with the n75 solenoid might make sense, also there is some talk about a ground under the battery that might be causing a short. Ill read the article again, its kinda long. Thank you
     

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