Cobb AP - DTC's versus CEL's

Discussion in 'Modifications & DIY how-to' started by Protocol, Mar 22, 2010.

  1. Protocol

    Protocol Member

    As experienced this weekend, it appears that Cobb AP's will not read (perhaps only some) DTC's. Only CEL's.

    I had a DTC for problems with the "Steering Angle Sensor" on my GR STI. I would not read this, even given the fact that the instrument cluster specifically disabled all VDC/ABS controls (not that I don't disable VDC anyhow 99 percent of the time).

    I know the AP will read true CEL codes because I've personally done it wil my AP. This was my first DTC though. I love the AP, but I thought that they were fully functional for reading all codes large or small.

    Guess not, or maybe there are just a handful that it doesn't recognize. This post is more of a FYI rather than a question that I am looking to get answered.

    I would like to know if anyone has experienced anything similar with their own AP before!
     
    Last edited: Mar 22, 2010
  2. integroid

    integroid Supporting Member

    This is just a guess but maybe the Cobb AP can only read codes from the engine management and not from the body control unit? I know the can-bus kind of makes it all one big happy family but who knows
     
  3. Protocol

    Protocol Member

    Ahh, that is a totally valid point. You'd figure that as popular (and mostly the reason it was released) would be to unify most of these autonomous sytems into a centralized one. I know that when I browse the service manual and look at the schematics for the yaw, g and steering angle sensor voltages and such they each ran to the DCCD controller, which appears to be a separate system mounted inside the ECU chassis (not positive... didn't want to crack it open). Sucks to rely on those codes and only be able to possibly "selectively" read them.

    A good test would be for me to deflate a tire and see if the AP reports that. That is a valid DTC that should get reported in the event of a failed sensor, etc.

    I'll try that and report back what happens in the near future.
     
  4. Its probably because the normal dtcs for engine have been standardized across the board for all manufacturers so emissions machines will work on all cars..
     
  5. Protocol

    Protocol Member

    I think Eddie's right though. Some of the BIU codes just don't get read. I did the flat-tire test (which is wired into the BIU as well per the service manual) and it didn't read that code either.

    I know it reads catalytic converter codes... Oh of course the emissions shit it will detect all day long... thanks again Cali. How can I ever repay for for my secondary ait pump!?

    From now on I would pretend that the AP will only read codes that are critical to the vehicles bottom line movement!
     
  6. Mike@TTR

    Mike@TTR Active Member

    You can always use a tactrix cable and there is a program you can get that will pull them. I know it is a pain to break out a laptop and all, but it works....along with romraider to log and that sort of thing.
     
  7. Protocol

    Protocol Member

    True that. I suppose I could un-marry the AP and test that out. I know you can mask codes with RomRaider too, which is nice for anything sensored that should be sensorless (I.E.: Secondary Air Pump delete).

    Installing the Cobb locks the ECU to the point where OS tools can't access it I believe, but I am not 100 percent about this. I would be a neat test to say the least :sx:
     
  8. Mike@TTR

    Mike@TTR Active Member

    Oh you don't have to unmarry to check things out. I was talking about with Cobb still installed. Feel free to call me if you have any questions!
     
  9. tolnep

    tolnep Member

    nope. dont need to unmarry. i bought a tactrix 2.0 cable to play with the logging and realtime views available in romRaider and it does all of that just fine. i actually go back and forth between romraider and access tuner race for both dashboards.

    at the end of a run, no matter what im running the last thing i do is connect up the tactrix and use learning view to look at the 4 part compenstation thing and the knock adjustment. you can look at the knock adjustment with ATR but not the 4 segment thing. learning view also shows OBDII codes which is interesting because every so often i get a cat inefficiency and EGT temp out of bounds, even though i have both turned off under Cobb AP. these codes all go away as soon as i turn off the ignition. i use that view to tweak my MAF on the lower end/closed loop. works good of this.

    i also have some software ODBII reading stuff that shows me additional stuff like all the emissions ready codes. i was most concerned after my fuel pump install to make sure my evap ready test passed.
     
  10. Mike@TTR

    Mike@TTR Active Member

    Correct. It is one of the many tools I use. I use everything at my disposal when tuning :)
     
  11. Protocol

    Protocol Member

    Nice. That is interesting. Looks like I need to get my clunker Windows XP laptop out and play around (read only of course) will some of the OS stuff. NO WRITING DAMN ME! Guess I'll need to get a new tactrix cable as well since mine is previous generation (if I even still have it around in a closet somewhere)...

    Ahh one day...
     

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