very confusing problem with 04 STI

Discussion in 'Modifications And Maintenance' started by Tim the Plumber, Apr 8, 2010.

  1. Tim the Plumber
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    Tim the Plumber Well-Known Member

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    Ok before everyone freaks out this is NOT my car, this is my buddies car back in Ohio (same buddy who introduced me to the STI). I thought I would post up on here and see if anyone else has any ideas. Please note: Symptoms may or may not be related.

    Car: 04 WRX Sti
    Mods: TBE exhaust, stage 2 tune, CAI intake.

    Issues:
    1)Diff gone crazy : Randomly while driving, it seem to not happen under and certain case but more totally random. The center Diff control display will come out of auto drop all the way down to the lowest arrow and start flashing. He does say he notices a "lack of power"

    2) Engine idle is very low

    3) Radiator fans turn on once the cars been turned off and keys removed. They will run until the fuse is pulled or the battery dies.

    4) Under acceleration (pretty sure WOT) the horn will sound

    5) Occasionally when the head light high beams were turned on the horn would sounds and not turn off till the fuse was pulled.

    Solution attempted so far.

    1) Checked all fuses and relays

    2) Went through wiring with multi meter and check all wiring

    3) Went through and double checked all ground connections

    Next solution: He found a used ECU that works and is going to install that in place of his current ECU.


    Any of your suby gurus have any idea.. If anything maybe will make for some good discussion. Besides I don't want to start working yet
     
  2. J.Rex
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    J.Rex Well-Known Member

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    Did this all start happening at once? Sounds like somebodies playing a joke your friend. Water damage to the electronics maybe???
     
  3. Tim the Plumber
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    Tim the Plumber Well-Known Member

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    problems came about in basically that order.. cant think of anyone that would have played a joke he keeps the car garaged, I cant think of that many of his friends that would have the know how to pull off a prank like that.
     
  4. idget
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    idget Want to pokéman? PM ShortytheFirefighter Staff Member

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    Did he buy an Audi STi?
     
  5. project/driven
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    project/driven Well-Known Member

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    It sounds like a bad ground, or maybe a positive cable grounding out some where. Maybe something is pinched somewhere and is triggered by vehicle movement or drivetrain slop under accel. Electrical problems suck, good luck man.
     
  6. ychanus
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    ychanus Well-Known Member

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    I used to have a Honda that does weird electrical things. And that ends up was a tiny bad light bulb that created a short somewhere. As soon as I replaced that bulb, everything works normal again.

    Though, I'm not sure subaru has this kind of issue.
     
  7. 2.5SubieRS
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    2.5SubieRS Well-Known Member

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    I had a problem like this on a 02 beetle i was working on at my old shop. The horn sounded everytime the left blinker flashed.

    Small Furry Creatures Plus Wires = One Epic Failure

    Im gonna go with pinched(chewed) wires, a nest in or under the fuse box, or a loose wire somewhere that is swinging back and grounding out on accel, and/or bad grounds.

    And when the say checked ground connections did they use a multimeter or just look at them?
    Because to use a multimeter to check engine grounds you have to isolate at least one end otherwise the electricity can just pass through a different ground and still make the ground in question read good.

    Also a simple and easy test to something that will cause thousands of random things to happen.
    Check the AC output on the alternator. AC current in a DC system can make all sorts of things happen randomly.
     
  8. Tim the Plumber
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    Tim the Plumber Well-Known Member

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    I'm pretty sure they pulled a bunch of the wiring and re ran all new ground, I am double checking with him now... also told him to take a look at the alternator see if maybe there is an issue there. Right now he thinks it could be related to a busted ECU. He is getting the replacement one in on Friday so he should know if that fixes the problem or not by then.
     
  9. AWDimprezaL
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    AWDimprezaL has more posts than you

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    Does he have some kind of ghetto but extremely overkill style stereo in it?
     
  10. Tim the Plumber
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    Tim the Plumber Well-Known Member

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    not really, just pioneer DVD flip screen I believe
     
  11. Dynapar
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    Dynapar Well-Known Member

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    I dont think that this is the problem. The DCCD is controlled by its own separate controller. Since the DCCD is acting wierd I would say that the problem is effecting the electrical for both the DCCD and ECU. This may require busting out a wiring diagram and a multimeter to sort out.
     
  12. bora28
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    bora28 New Member

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    I LOLed!
     
  13. TSTRBOY2004
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    TSTRBOY2004 Well-Known Member

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    as did I...
     
  14. Tim the Plumber
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    Tim the Plumber Well-Known Member

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    heres a new tid bit.. if he hits the DCCD button and holds it for more then a second the horn sounds until he hits it again... also he said when he pulls the fuse for the radiator fans but not the relay he hears what sounds like an electrical starter click coming from somewhere near the MAP sensor....

    possessed car is possessed
     
  15. Tim the Plumber
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    Tim the Plumber Well-Known Member

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    So i talked to my buddy and was able to pull this write up from his local boards I think we might be gettign closer to the cause...

    ok, so i had a post up earlier about my cooling fans coming on when the car turned off...the problem has escalated into a whole bunch of random events now. any input is appreciated. Here is a breakdown of what happens and when it happens.

    Car Off: Horn honks continuously, main cooling fan turns on (only sometimes, not everytime)

    Key turned to on, engine off: Everything normal until I hit the DCCD manual button. Once button is pressed and DCCD goes into manual mode, the cooling fan turns on and the horn honks. If I rotate the DCCD dial to the bottom most position and lock it in everything turns off, if I leave it in any other position the fan and horn will run until the DCCD then goes into failure mode.

    Engine running: everything normal except for the DCCD goes into failure mode most of the time shortly after driving the car. Car has a rough idle some of the time.

    I have tried replacing the ECU and that did not solve the problems. I have checked every fuse and relay probably 10 times. I have the car torn apart currently in my garage trying to trace wires to see if there is a short anywhere, but that is very difficult to do as most of the wires are encased and running behind the dash/engine.

    Any clues as to why the DCCD would also somehow be controlling my cooling fan and the horn or as to why the horn/fan stays on continuously once the car turns off?

    i tried to get into the dealer but they have nothing open until next week, I start a new job next week so I can not exactly take time off to take my car in. ZB has looked at it already and came up with no solutions either.

    If anyone would like to come visit this circus sideshow of a car they are more than welcome to, $5 admission at the door.
    __________________
    04' WRB STI
    Perrin 3" stealth turbo back exhaust, cobb SS, kartboy shifter bushings, exedy stg. 2 clutch w/ACT streetlite flywheel, K&N SRI, custom tune by matt @ 555 motorsports.


    also he was able to pull DCCD codes and ABS codes...

    DCCD system and got codes 11-14, 31, 33, 34.

    11-14 are "Open or Short circuit" in all of the ABS wheel speed sensors, 31 is open or short in manual mode switch, 33 is open or short in brake switch, 34 is open or short in ABS switch

    ABS Codes
    44 - A combination of AT control abnormal
    51 - Abnormal Valve relay
     
  16. J.Rex
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    J.Rex Well-Known Member

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    Check out the wiring around connector F45, every problemed part listed has some wire going through that connector. Since you're getting all open or short error codes, sounds like the connector is loose or corroded or those wires are rubbing and shorting out several wires. It looks like that connector might be deep under the dash, so have fun trying to find it.

    http://guibo.com/~guibo/subaru_doc/Impreza_2004/7._Wiring/50._Front_Wiring_Harness.Pdf
     
  17. J.Rex
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    J.Rex Well-Known Member

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    ABS valve relay has a wire through F44
    Front Left ABS wheel sensor has a wire through F45, don't know about the other sensors, they don't have any wires in that area
    Constant power to the DCCD controller goes through F45
    Horn Relay wire goes through F45
    The Fan relay wires go through F45
    Brake switch is in that area
    I think the ABS Switch code has to do with the abs valve relay, cause what else is an abs switch?
    Do the brake lights work properly?

    I would put my money on some worn wires in the area of the F45-F44 connectors shorting.
     
  18. Tim the Plumber
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    Tim the Plumber Well-Known Member

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    jesse, great in put! I'll let you know if that fixes it
     
  19. J.Rex
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    J.Rex Well-Known Member

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    updates?