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linear valve offset fubar

Discussion in 'Gen 2 Prius Technical Discussion' started by Tombukt2, Dec 28, 2023.

  1. Tombukt2

    Tombukt2 Senior Member

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    So I got to actuator off of this fugly '08 Prius that look like it had been through I don't know what and back horrible looking but the brakes all worked no lights on the dash I removed the actuator from this car put it in the carport for about the past 8 days. I removed the actuator that I had installed on the '08 green car that still had ABS VSC and the! Amber still lit and the brakes are horrible. So I did the swap today in the green car with the fugly ugly cars actuator got it all installed I have no air guaranteed went through the complete brake bleeding process in tech with no issues when I clear the memory and do the linear valve offset learning the ABS and the VSC and the Amber! All flash fast The VSC and ABS are going faster than the! The b r a k e in red light never flashes or does anything I have done this with the emergency brake depressed and with it not in the ready mode and in just the ignition mode at the end of the offset valve learning window something supposed to flash fast one more time and then you're done I never get the last fast flashes at 37 seconds the Amber stop flashing and then on out to zero seconds left nothing ever flashes again The brake red light is on and the ambers are still lit If I unplug the cable cycle the car and make it ready my Amber's and my brake red light remain on but when I drive the car my brakes are almost perfect everything works fine Regen breaking is working all of it as it was before but before it seemed like just the rears were working or something like that The car was squirrely when you were breaking if you weren't careful now it's not now I can slam on the brakes everything seems pretty normal. So what's up with the offset learning business Why can't it do that when it's doing that in the window I can hear all the wheels clicking and the brake pump is pumping off and on and the lights are flashing and all that's happening but it just doesn't ever learn how long am I supposed to wait for the end lights to flash when learning the linear valve offset 5 10 minutes I usually give it 60 seconds they don't flash I shut it all off restart the car recycle the car and the lights are still on but everything is working just like my car with no lights The pedal feels just like the '09 with no lights on everything seems to be working very well I just can't get rid of the lights what say y'all?
     
  2. Brian1954

    Brian1954 Active Member

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    What trouble codes do you have?
     
  3. Tombukt2

    Tombukt2 Senior Member

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    Sorry I left that out It's 1365 and 1368 One of them is not learned and the other one is not set both involving the linear valve offset or whatever it's called they will not clear can't go away nothing but everything seems to be working just like my '09 when I change the actuator in my '09 I didn't have to go through any of this dance I threw the actuator in there bled it and the lights were never on and that was a used actuator from God knows what year model car and all that It was a very sloppy purchase I just yanked it out of a car and dropped it in the '09 and at the time didn't even have tech I manually bled like you do a regular car lights never were on the thing running great this car the '08 same situation this is the second actuator still can't get the lights out this is one of the quietest actuators I've ever owned in a generation too also. It is extremely quiet and it rarely comes on I have to pump the brake pedal a couple of times for for me to hear it coming on so there doesn't seem to be any accumulator leaking nothing no air in the system it just can't learn whatever linear offset is I mean personally at this point I don't even care because the brakes work great put a piece of tape over the lights for now until all the stars align and something else happens I'm certainly not going to run out and pay $1,300 for a new brake actuator I can't even be guaranteed that that will put the lights out and then they'll tell me it's my fault and Toyota didn't install it and there's no warranty and God knows what else so we're not doing that the car brakes. Without all the jumping and lighting field and sliding and any of that so I can only say it's successful enough I guess. This is why people don't want to fool with these because even if you spend the big bucks and if you can't get the light out and can't get whatever to go on John q customer is the one who's going to be shat on. And having to jump through hoops trying to get the money he gave up back which means he's going to lose some of that money and fees if he gets anything back.
     
  4. Tombukt2

    Tombukt2 Senior Member

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    I did notice upon taking the car out for 12 mi drive that my regenerative braking is way stronger than it's ever been I take my foot off the gas there is a little lag between seeing the aqua colored lines going backwards from the axle to the electric motor to the battery from the yellow color but when it does come on it'll almost stop the car and know the brakes aren't sticking that I can tell if I flop it to neutral from the regen breaking the car will roll on out for a minute a while. So taking my foot off the gas to the time I see the aqua lines going backwards where the yellow ones were on the display indicating regen breaking is a few milliseconds longer with the old actuator in place the minute I took my foot off the gas I could feel the electric motor braking and all of that but it wasn't near as strong now I take my foot off the gas it takes a few milliseconds for me to see the blue lines on the display or the aqua lines on the display and feel the braking but when you do it is noticeably stronger If I'm not pushing down very much on the pedal the ABS pump almost never comes on It's only when I go down to the point of squeezing the pads soon as I let go of the brake pedal the pumping almost immediately stops. When I'm sitting in a parking lot even with the engine running and then with it not and just sitting there ready pump doesn't come on very often I'm going to bleed it again in the front just to make sure I need to take it out run it up and down and break a few times and check the temperature at least on the two fronts and see if we're close.
     
  5. Tombukt2

    Tombukt2 Senior Member

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    I'm guessing this linear valve is inside of the actuator? So there's nothing external that could really be causing it not to learn its calibration. When I hook up tech to run the linear valve offset it tells me there are certain preconditions that need to be met before running the calibration see the manual I can't see the manual does anybody know what the preconditions are for running the linear valve offset learning portion I have erased the original whatever that is you know with the other part of the software it's just not been able to learn the offset that it's trying to when it's running the software. But I do not know what the preconditions are like do I need to have the parking brake down I've done it both ways doesn't make any difference.
     
  6. ChapmanF

    ChapmanF Senior Member

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    I'm pretty sure the parking brake does matter, because if you look in the manual for the procedures "when not using the Techstream", there are two different ones where you use the same jumpers and the same everything else except for whether the parking brake is on. Seems to me parking brake off gets you the linear solenoid offset procedure, parking brake on gets you whatever the other procedure is.

    It's probably also the case that something in an old actuator could be worn, and if it's worn enough, the value learned for the solenoid offset won't be in the allowable range so the learning fails.
     
  7. Tombukt2

    Tombukt2 Senior Member

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    Yes that seems very plausible here and in most cases because it looks like most people that have this problem wind up spending the $1,200 or whatever it is dollars for a brand new dealer acquired actuator that seems to be a fact I got lucky with my '09 and no tech and that car is still on the road running like a top We can't kill it so we'll just chalk it up to that because it looks like that's extremely rare to happen for me it's happened once with the '09 The other times I've mounted a used actuator in a generation 2 I have had the linear valve and I think that's it for codes but the brakes seem to work wonderfully I don't know what the linear valve does so I don't know what I'm looking for to be not working correctly The brakes seem to be working very nicely there's definitely no air The bleed procedure was no problem to get through on this vehicle pumping the brake 30 times all this and that fine I had pre-charged the actuator with fluid before I hung it so it was nice and wet all of that bleeding was no problem it's just the linear valve business It does the linear valve keep the brakes from not functioning properly.? because it seems to me their functioning very well the other actuator that was in the car that had the same lights on breaking was very flighty terrible now it's almost spot on like the '09. But it can't learn what it needs to learn.
     
  8. Tombukt2

    Tombukt2 Senior Member

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    Remember this is the car we have $700 in has a $240K on it Is that nice green color leather interior drives real nice and is real clean inside The brakes seem to work real well so I guess for now I'll just cover up the orange lights with the black piece of tape any minute now all these generation twos that people have spent money putting these brake parts in and catalytic converters on and all this will be heading to the junkyard with wrecks and all of that kind of thing soon. So those 2-year-old actuators and 9-month-old actuators and all that sort of stuff should be starting to show up in the junk yards which then they'll get picked and put on eBay but still. So I guess we'll just wait it out this is the car that I can't get a title for because the VIN is dead I have it on my insurance and I just drive it with another tag from another generation too in the southeast all they care about is financial responsibility the wrong tag being on the car that's a $10 fine if any so we'll just let it rip.
     
  9. TMR-JWAP

    TMR-JWAP Senior Member

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    Driving with the linear valve offset error code is typically not a problem in dry weather when the tires have plenty of grip. You may notice the brakes being slightly grabby when slowing down and reaching around 4-5 mph. Unfortunately, you're going to head for some excitement when the roads get wet or slippery and one or two wheels lock up and make the car go part sideways, or the car doesn't even slow down. Seems like when one wheel locks up, pressure is released from all 4 when this code is present. All you can do is release the brakes and press again, praying to God a wheel doesn't lock again so you can stop in time. Speaking from experience. If it's actually an emergency and that happens? You're screwed and someone's life is going to change quickly. Hopefully it's you driving the car, so you know a bit about what to expect. If it's your wife or kid, well, it may get real exciting for them real fast.........
     
    #9 TMR-JWAP, Dec 28, 2023
    Last edited: Dec 28, 2023
  10. Tombukt2

    Tombukt2 Senior Member

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    No no one's allowed in any kind of car that's doing anything funny except for me they don't even have the keys they have their own all that nonsense so it will only be me and we are in the thick of winter right now couple of weeks ago with the other actuator that was a used actuator too The brakes were way worse I mean the car floated around the road like a Cadillac when you touch the brakes Regen and all that worked but it was very flighty especially like coming up to a stop sign and getting on the brakes like more than usual because you didn't start early or whatever normally I don't ever even activate the hydraulics to be honest about it I'm on these backcountry roads so on and so forth You can just regen up to a stop sign nobody cares you're out in the country so on and so forth so it won't be any problem like that no one will be driving the vehicle if it goes berserk and crazy all that'll do is go in the drink or the ditch be changing how I get home I guess but hell I didn't have any problem driving the '09 when it only had the right front caliper working I wouldn't even rate it as an experience but it was quite funny but I drove it around like that about 2 days.
     
  11. Tombukt2

    Tombukt2 Senior Member

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    So what actually happens when the pump runs the accumulator fills up then when it bleeds down where does that bleed down of the accumulator go in that big chunk of aluminum that is the actuator assembly It would seem to me that would be under some pretty good pressure and it would try to head to valleys and ways that lead to wheel cylinders and calipers? It's not going out on the ground it is liquid pressure not air so it has to somehow dissipate in the valleys and ways inside that aluminum assembly and not go to any wheel cylinders or calipers? So there must be a heck of a area inside that aluminum block to just catch bleed down from the accumulator whenever that may happen That's very strange and I've noticed that no matter what's going on in my Prius I never not have brakes when the accumulator's down and the beep comes on I know that the brakes are going to be like a Dodge truck with four-wheel drums and the master cylinder bolted to the firewall with no brake booster and as long as you know that you're good No problems driving at all I'm not understanding how my accumulators bleeding down to the point where the beep comes on and then if I pull over and listen during the beep the pump is not even running to pump up the pressure to turn the beep off if while sitting I hit the brakes once or twice the pump will come on pump up the pressure put the beep off. And the check engine light never lights during any of this so it seems to me that the yellow exclamation point is kind of like the check engine light for the ABS VSC and TRAC system just what it seems like from my observation which doesn't mean squat.
     
  12. ChapmanF

    ChapmanF Senior Member

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    Goes back to the reservoir, same as it does when you've been braking and you release.
     
  13. Tombukt2

    Tombukt2 Senior Member

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    Oh that's very cool to know that because I don't see any level changing at all going on in the reservoir ever even if I have somebody standing on the brakes and the pump is running full time and then we take our foot off the break and wait for the bleed down to occur Don't see anything and now just it random times the beeper will come on and I'll have the old style truck brakes and if I push the brakes once or twice just while I'm driving the beep will stop and it seems the accumulator pumps up in the brakes are back to normal and then it may be an hour before it beeps again just driving around normal traffic. It's really quite weird but seems like you always have brakes in the Prius with the exclamation ABS and VSC lights on if you get a beep you'll have brakes like 1967 and if you don't have a beep you have full breakage. At least that's what we're seeing here with these two vehicles that I've dealt with this actuator business.
     
  14. Jeffster06

    Jeffster06 New Member

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    @Tombukt2 - did you ever end up fixing this problem? I'm having the same symptoms and debating what to do next because the linear actuator won't calibrate and the codes won't clear. Thanks!
     
    Tombukt2 likes this.
  15. Tombukt2

    Tombukt2 Senior Member

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    The linear valve won't clear and relearn because there's something wrong with the actuator I pulled another one off a few days after all these posts put it on didn't even have to do anything with the linear valve offset or any of that Just bled the brakes lights went off everything's working fine another used actuator the one I took off I threw out I'm getting these for near nothing generally speaking so when they don't work I take all the fittings and stuff off put a big mark on the thing and put it in recycling.
     
    #15 Tombukt2, Apr 19, 2024
    Last edited by a moderator: Apr 21, 2024
  16. TheLastMojojomo

    TheLastMojojomo Active Member

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    Are you doing the entire Linear Valve Offset Procedure correctly? You have to clear the memory of the Linear Valves (reset memory function) before calibrating them... otherwise the Calibration won't work. My video below explains step by step exactly what you need to do:

     
  17. Tombukt2

    Tombukt2 Senior Member

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    And this was a new actuator you bought right? Like $1,500 worth a part? Not used in other words?
     
  18. Jeffster06

    Jeffster06 New Member

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    The one that wouldn't calibrate was a used one from eBay, but bought a new one from Toyota parts online during their April 25% off sale and got the new one for $900+tx and picked up in hours at my local dealership. Installed it and everything calibrated just fine and we're back on the road. Thankfully was able to get a refund on the eBay part, but didn't love having to do the job twice haha.

    And yes, I did reset the memory first. Tried several times on calibrating the used one and even rebled the system and still no go, so bit the bullet on a new part.

    Thanks for the replies guys :)
     
  19. dolj

    dolj Senior Member

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    You probably found the reason it was removed from the original car. Second-hand with these units is a crap shoot.