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PCS need a ECU expert

Discussion in 'Gen 1 Prius Plug-in 2012-2015' started by pjw3, Jun 17, 2022.

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  1. pjw3

    pjw3 Junior Member

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    We have a 2012 Plug In with the PCS option.
    Car was sold to us with undisclosed damage and after 1 month the PCS gave out. It was damaged in a collision.
    Who needs the stupid PCS? Well, the cruise control needs it, just in case you don't know how to apply the brake pedal. (Doesn't "break" or "breaks" drive you nuts?)
    Anyway, the PCS alone lists at about $2100 and then you get to install and pay someone to come calibrate it at $250 - $400 a pop. If the badge ($600 or so) is damaged, order that up and then pay them to come calibrate again. All so you can have the car maintain a safe following distance. Ugh.
    The part is almost impossible to find used, it was specific to 2012. Later years used a different unit. Run the VIN through Toyota's VIN ID and very, very few will show "PCS" buried it the end of the "safety features" on the build sheet.
    The only work around that I could imagine is to order a ECU for a VIN with a similar high option package that does not list PCS, but that is a dangerous path.
    So my little Prius fiends, who wants to delve in?
    Can anyone comment on where the PCS signal is routed to disarm the cruise control.
    For all I know the engine ECU may not even be the right place to look.
     
  2. LeviSmith

    LeviSmith Member

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    Try thing on cruise and then hold the cruise stalk toward you for a few seconds. Then you should be in old fashioned cruise mode. It's in the owner's manual on Toyota's site. I have to do it once in a while when the pcs gets too much ice build up.
     
  3. pjw3

    pjw3 Junior Member

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    Thank you for the tip.
    That makes sense, but I tried it and it did not seem to override the fault. I will review my manual again.
    Again, does anyone have knowledge of what control module might be modified to prevent the vehicle "looking for" the PCS?
     
  4. LeviSmith

    LeviSmith Member

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    Sorry it's push the cruise stalk for a few seconds not pull I just tried it myself
     
  5. pjw3

    pjw3 Junior Member

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    I don't know how to say thank you with enough fanfare.
    I have been trying to figure this out for 3 years since my wife was sold a beautiful used car until we discovered how well the seller had hidden that accident history and the zip ties holding the PCS in place, just long enough to get the car home. Wicked liar that he was.
    I have probably spent close to 120 hours trying to repair, looking for new and used PCS units, scanning Copart for cars using the Toyota while lookup to figure out what 2012 cars even have the PCS, learning that the 2012 is a single year's specific unit.... I can go on and on.
    I was about to order a discounted $2300 new PCS unit and hope that it could be calibrated, this was my last-ditch effort and you totally saved me!
    Through all of this, no one on Prius Chat, ECU programmers, Dealers, body shops, no one else has understood and been able to identify what I had hope was there all along, a way to disable PCS, (no, not that dumb button under the steering column!) just so I (or rather my wife, even worse) could just use the stupid cruise control. But you did it.
    My little ADHD brain could not get unstuck and out of the PCS section of the manual, to read the Cruise Control section and to find those instructions. A combined 50 or so pages of disclaimers was too much.
    I truly cannot thank you enough, would $1,000 to Ukraine relief (International Red Cross?) make us square?
    The Gen II and beyond Prius is in my mind, the height of automotive technology, through at least 2015. It is the ultimate expression of waste not, want not. A 50-mpg camper, commuter and van rolled into one expression of human accomplishment. I love the weight, comfort (oh those seats!) and mileage of my wife's fully optioned 2012 Plug-In, but the simplicity of my (4th) Gen II is hard to beat. I have put my family through at least 8 with 4 currently on the road. The Prius Chat community is a huge part of what makes this such a great car and is also an expression of what the internet is, at its best.

    Where in NY? I travel from 20016 to 06039 to 05468 and beyond. As little 20016 as possible.
    Still on that 2004.
    Can I pick up a 2006 or 7 for ya?
    Let me know if I can help.
    Thank you.
     
  6. LeviSmith

    LeviSmith Member

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    Glad I could help!
    Sorry, guess I've been a member and haven't updated my profile for quite some time. I've had a few vehicles since the 04' Prius. Currently I've got a 12' Advanced Pip just like yours. I absolutely love the radar cruise but for $2300 that would be a tough decision...
    Got mine just over a year ago, shipped from CA(Boggles my mind that a 10 year old car exists that has no rust and bolts aren't seized, etc! Never happens in salt happy NY!) I use it a few days a week for Uber so I've put about 60K miles on it so far. Semi-expectedly the headgasket went out at aound 215K miles, but the swapped in 2016 engine seems to be working well.
    I am vaguely keeping an eye out for a cheap 16' or newer fully optioned, preferably AWD or Prime 5 seater... Just in case something happens to this one. Love my other car, a Crosstrek, but using it for Uber as a backup costs about another $30+ per day in gas compared to the Prius. Though with the prices of used cars at the moment, if I had to replace it, I'd give serious thought to something like a Bolt or Kona EV... Still far from ideal for my purposes though...
    I'm about an hour south of Rochester, down where I390 and I86 merge.

    Enjoy your cruise! :)
     
  7. pjw3

    pjw3 Junior Member

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    bisco likes this.
  8. LeviSmith

    LeviSmith Member

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    Head gaskets I believe are a problem 2010 through at least 2015. Engine was changed in 2016 to supposedly fix it, but I think I've seen one or two people with newer ones and a lot of miles say they had a problem. Most people seem to get a slight leak they can limp on for some time. Mine went rapidly from no problems at all to MAJOR engine shaking every time the ICE started up and drank half the coolant bottle on my 65 mile trip home.

    Yep, from what I've looked I'd have to go at least 2020 to get a 5 seater Prime and for the prices of the used ones, I'd probably be better off with a new one with discounts. Haven't seen anything remotely like the $6K I paid for my plug-in last year... :)
     
  9. black_jmyntrn

    black_jmyntrn Senior Member

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    Well, I'm just getting here and now want to see what I can do in the ECU...I have the PCS and I relocated it to the lower grill so my winch cord can travel through the while where this part once was.

    The only thing I am trying to get a hold of is the calibration tool I guess you call it, guess you set it out front of the Prius to calibrate it. Once I find it ill be happy.

    So wait.. is your sensor unplugged or just damaged?
     
  10. pjw3

    pjw3 Junior Member

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    Sorry that I missed this. sensor was damaged. Most body shops have a contractor come in and do the calibrations although almost every car has them now and so they are beginning to have the necessary machinery to calibrate. Ask around, the service is not inexpensive. I hope that you caught the work around. After a few weeks our PCS has actually recalibrated itself and now works w/o the work around.
     
  11. Mendel Leisk

    Mendel Leisk Senior Member

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    More likely the EGR (Exhaust Gas Recirculation) system reliably clogging up with carbon on 3rd gen (2010-2015) was the cause of head gasket failures. It was revised with advent of 4th gen (2016-2022), and I don't think there's been a single head gasket failure reported here. 4th gen did also add plastic baffles in the coolant passages of the block, could be a factor as well.