C1247 ECU Skid Control replacement?

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by mttaylor1, Mar 17, 2014.

  1. mttaylor1

    mttaylor1 New Member

    Joined:
    Mar 17, 2014
    6
    0
    0
    Vehicle:
    2004 Prius
    Model:
    II
    2004 Prius (not sure the package) with 130K
    Did quite a bit of reading but wasn't seeing an exact fit for my situation so figured a post might be worth a shot.

    In 2012 we had the ABS and brake and I believe VSC sensors go off and the car was behaving very erratic.
    Lurching forward and a non responsive brake pedal.
    Dealer logged a C1247 brake pedal stroke sensor but reset it and sent me on my way (after some diag fees)

    Yesterday we had the same experience (pretty scary) and ABS, Brake and I believe VSC light up.
    Towed to Dealer and logged another C1247 code and was told that we should replace the ECU Skid Control Unit.

    Part number 8954047060 $1921 at dealer (see $90 used on ebay)
    And $400 labor.

    Reasonable diagnosis and repair costs?
    Seems like a reset of the sensor/computer got me almost another year until this most recent event but we don't want to drive knowing this condition could pop up again.

    Thoughts, suggestions much appreciated!
     
  2. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,180
    6,275
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Either the brake pedal stroke sensor or the skid control ECU is at fault. I am wondering why your dealer did not suggest replacing the stroke sensor first, since that is less costly than the ECU.

    I would suggest that you first replace the stroke sensor with a new part; then if that doesn't help, replace the ECU with a used part.
     
  3. mttaylor1

    mttaylor1 New Member

    Joined:
    Mar 17, 2014
    6
    0
    0
    Vehicle:
    2004 Prius
    Model:
    II
    Thanks for the prompt reply and input Patrick. I'll run it by the dealer in the morning and see what they say.
     
  4. mttaylor1

    mttaylor1 New Member

    Joined:
    Mar 17, 2014
    6
    0
    0
    Vehicle:
    2004 Prius
    Model:
    II
    Interesting, when looking for a used ECU on ebay.... all the cars had front end damage. Could these be tied to a "bad" ECU and the same symptoms my car experienced? Or just coincidence?

    Just did an ebay search on 8954047060
     
  5. mttaylor1

    mttaylor1 New Member

    Joined:
    Mar 17, 2014
    6
    0
    0
    Vehicle:
    2004 Prius
    Model:
    II
    The Toyota technician said everything (including the pedal stroke sensor) checked out OK.... so the TSP guides them to replace the ECU to the tune of $1921 + $400 labor.

    2004 Prius with 130K miles... blue book is $5200... $2200 in repairs leaves me wondering if I cut my losses and go with something a bit newer?
     
  6. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,180
    6,275
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Yes, or else have a used part installed if your dealer is willing to do that.

    Try autobeyours.com as a good source of used Prius parts.

    Typically a Prius will be totaled as the result of a front-end collision since the SRS system would have deployed and there are many costly parts in the front that would be damaged. So it doesn't surprise me that the eBay parts are coming from cars with front-end damage.
     
  7. mttaylor1

    mttaylor1 New Member

    Joined:
    Mar 17, 2014
    6
    0
    0
    Vehicle:
    2004 Prius
    Model:
    II
    Do you happen to know how to reset the ! and BRAKE light sensors when they are tripped?
     
  8. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,180
    6,275
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Apply a jumper to pins 4 and 13 of the OBD-II connector; do a search for how to reset skid control ECU DTC.
     
  9. Gib

    Gib New Member

    Joined:
    Mar 21, 2014
    2
    0
    0
    Vehicle:
    2008 Prius
    Model:
    Two
    My wife's Prius is a 2008 model 1224A (package 2 including VSC) with 71,000 miles.
    Recently while my son was driving it, it displayed the common 4 warning lights on the dash:
    BRAKES / ! / ABS / VSC
    and the brakes became very touchy: grabbing rhythmically. The brake pedal itself doesn't pulse, but it's as if the brakes themselves are pulsing about once or twice a second. He drove it for a couple of days like this until he could get it back to me, then I drove on a couple of short errands-no change. I had a mechanic friend check the codes: C1247. He ran the Toyota Tech software and it came up with nothing out of spec. He did notice that there was a Tech Service Bulletin in 2012: T-SB-0174-12 "overly sensitive monitoring logic". Could this be the root of the problem?

    For now he cleared the computer code: the warning lights are gone and the braking is normal again. I'm driving it carefully to see if I can tell what triggers the malfunction. So far 3 short trips and all seems normal again.

    (Hopefully not to confuse the issue, but we had similar braking problems like this almost 3 years ago, at 50,000 miles. The braking symptoms were the same and the same 4 warning lights, but the codes were different: C2300, C1241, and C2318. The dealer replaced the 12V auxiliary battery, cleared the codes, and it was fine for almost 3 years. Even though we're getting a different code now, could it be time to replace the 12V battery again?)


    I see by searching the forum that several people have had trouble with the braking system, often throwing code C1247. It also looks like there have been 4 different approaches to fixing the problem, but none of them seem to be definitive, often doing any combination of the 4 fixes and then having the problem come back.
    1. adjust or recalibrate the brake pedal stroke sensor
    2. replace the stroke sensor
    3. replace the ABS ECU
    4. clear the code

    Has anyone determined what is actually causing the problem and what the proper fix is?

    Thanks,
    Gib
     
  10. mttaylor1

    mttaylor1 New Member

    Joined:
    Mar 17, 2014
    6
    0
    0
    Vehicle:
    2004 Prius
    Model:
    II
    Hi Gib, in my case I was told that all diagnostics came back OK and that the TSB was to replace the ECU. I had the sensors reset and drove the car off the lot only to have them all come back on the next day (yesterday). Last time this occurred I went a whole year without seeing them again.

    The service technician and adviser (I had them both there to pick their brains) made no mention of checking the batteries but that all the C1247 diagnostics came back OK.

    The service department tells me that ordering the new ECU (part #8954047060) has "updated logic". Yet when I talked to two other Toyota parts departments they say that part number is the same as the original 2004 that is in my car.

    I have read many forum posts on here and it all seems like a guessing game. I don't want to roll the dice to a tune of $2300 to have it not fix the problem for good so I'm still trying to decide my next move.
     
  11. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,180
    6,275
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    The following thread contains my comments on my 2007 experiencing this problem (at the time, the car was owned by my dad.) Basically, the dealer first tried clearing codes; then replaced the skid control ECU, then finally replaced the stroke sensor. The problem did not recur after that third service was done, the car has been driven 50K+ miles since the final repair and is now being driven by my daughter.
    See my posts 45, 48 and 54 here:
    BRAKE FAILURES ON 04+ PRIUS | Page 3 | PriusChat
     
  12. Gib

    Gib New Member

    Joined:
    Mar 21, 2014
    2
    0
    0
    Vehicle:
    2008 Prius
    Model:
    Two
     
  13. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,180
    6,275
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    Hi Gib,

    Yes. I doubt that both the stroke sensor and the ECU had failed. Since the problem continued after the ECU was replaced, it is reasonable to me that the stroke sensor was the actual failed part.

    As a general rule, if there are two parts that might cause the failure it seems reasonable to replace the less expensive one first, if you are the one paying for the repairs.

    In my dad's case, Toyota was paying for it so we allowed the dealer to let the mystery unfold over time.
     
  14. cajunprius

    cajunprius Junior Member

    Joined:
    Nov 12, 2014
    6
    1
    0
    Location:
    Lafayette La
    Vehicle:
    2005 Prius
    Model:
    Two
    Gentlemen, I am having the same problem as described above. Where do you suggest I purchase a stroke sensor?
     
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

    Joined:
    Mar 8, 2008
    18,180
    6,275
    0
    Location:
    Green Valley, AZ
    Vehicle:
    2015 Prius
    Model:
    Two
    From one of the Toyota dealers that sell parts at a discount over the web.
    parts.com is a source that I have recently started using. Basically that website will send the order to a Toyota dealer for fulfillment.
     
Loading...