Debugging ABS Issues on 2 gen 2s

Discussion in 'Gen 2 Prius Technical Discussion' started by Tom Parsons, Jun 25, 2022.

  1. Tom Parsons

    Tom Parsons New Member

    Joined:
    Jun 25, 2022
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    Location:
    Alabama
    Vehicle:
    2005 Prius
    Model:
    II
    So I have 2 gen 2's with different ABS issues. One I just replaced the pump in (2005), the other (2006) needed to be bled after someone unknowingly tried to bleed it the traditional way (I purchased it this way). I got both cars for $1200 each this year, the 2005 is my daily, the 2006 is my fix and flip.

    Both of these cars have been a uphill battle of brake issues, all caused by previous owners. I drove my 2005 around with lines running straight off the master cylinder to the wheels for 2 months because the actuator was leaking so much out a bad fitting.

    2005: Has Code C1253-138, which is listed as a abs relay issue. The subcode is for low voltage coming from the skid control ECU to the actuator. Techstream reads the ECU input at 0.0V (MTT). I'm assuming this might be the connector. The brakes work fine, powered friction brakes on all 4 wheels, actuator motor runs at reasonable intervals, but no regen and all brake lights are ON. I'm just driving it like it is but I would like regenerative brakes. I guess ill take the wiper assembly off and probe at the harness, but any help would be appreciated. I have swapped relays to rule that out.

    2006. Has code C1246-102. Code is for different pressures (voltages) on each master cylinder pressure sensor. Pedal is soft but the powered brakes work fine, albeit the pump runs more than I like. Failsafe mode does not work (pedal soft). Techstream says the master cylinder pressure sensor should be under 0.9v at rest (both sensors stay at 0.43 which is fine), but normally operate up to 5v, but I get at most 0.66v when the pedal is depressed. Ive tried bleeding every way known to man and techstream (relays pulled, pumping the brake pedal with a bleed bottle till my leg hurt). I'm thinking a possible bad master cylinder or stroke simulator (the cheap part thankfully, the part that feeds the abs unit), but it could just have so much air in it that its inoperable. I was wondering if anyone has had this same issue.
     
  2. Tombukt2

    Tombukt2 Senior Member

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    Vehicle:
    2009 Prius
    Model:
    Base
    Well well interesting I have a 2005 that basically had the same problem I tried to change the accumulator pump assembly and could never get the car to run again probably because it had a very seriously failing hybrid battery that I didn't know about at the time because the car was driving fine I still have that 2005 sitting right here I'm not going to fix it it's parts have been taken off of it. I now drive a 2009 that I've been driving for 2 years with all the dash lights on and all the brakes working fine with regen working and everything just no ABS I can lock up all four wheel wells and smoke the four tires it looks really cool. Just the other day I had a left front caliper basically not retracting wore out the inside pad I knew it was happening so I pulled the caliper off the '05 to later five looks exactly the same put it on the car cracked the bleed screw let fluid drip out till I saw the air push out a big bubble and drip drip drip. Now the '09 has only the right front caliper grabbing and it heats up fast so basically no brakes. I have bled and gravity bled until the cows come home I don't see any air all the fittings drip accordingly not pushing any air out really strange so I have supposedly a rebuilt accumulator pump assembly here that I'm installing right now we'll see what happens. I saw a video from Giovanni I think is his name with an 09 2 years old on YouTube He replaced his accumulator pump assembly from some remanufacturing part I'm waiting for him to tell me where he got it and he says he put the car all back together and bled with a mighty vac no text stream cleared the codes with a cheap inNova ABS code reader or it has ABS capability. And has been driving fine ever since and if he would have realized taking the wiper tray out he could have lifted the pump straight out and left the inverter in. What say y'all???
     
  3. SFO

    SFO Senior Member

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    Vehicle:
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    Welcome to PriusChat!!
    Here are the workups for DTC C1246 / C1364 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/repair%20manual/04pruisr/05/21avn/cic12464.pdf

    Though the above online manual is dated (2004), there doesn't appear to be an INF or detailed code listed with subcode 102.

    In case someone needs the other workup for C1252 / C1253 : https://share.qclt.com/%E4%B8%B0%E7%94%B0%E6%99%AE%E7%91%9E%E6%96%AF%E5%8E%9F%E5%8E%82%E8%8B%B1%E6%96%87%E6%89%8B%E5%86%8Cpdf%E6%A0%BC%E5%BC%8F/Repair%20Manual/04pruisr/05/21avn/cic12525.pdf

    FYI : you're moderated until you've posted 5 times.
    Never heard of someone attempting a ABS pump swap with the inverter still in place, seems like it would make the job more difficult.

    Have you successfully tried this technique, and how much time was saved during the pump removal and replacement process?
     
  4. Tombukt2

    Tombukt2 Senior Member

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    2009 Prius
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    Base
    The only way that will work is if I can get the 212 mm bolts that hold the weight on from the bottom if I could do it relatively quickly with a long extension and a 12 mm blast those two bolts first thing looks like that weight will come right around and drop into my hand I might ought to not put it back this go around I put the weight back if the weight wasn't there you could undo three nuts and lift the pump right out of the bracket after the lines are undone and it's unplugged with the wiper tray out it looks like access to the lines the three nuts that undo the rubber mounts and the front nut on the pump mount itself The silver bracket that holds the lines to the pump assembly I got rid of those brackets on reinstall because they're just not needed they look pretty but I don't need them and it was easier to put the lines back in and rethread without the brackets trying to hold the lines I guess I could pop them back on but all these things held down like this or just not needed we will see shortly The car was dead quiet when I drove it before no rattles no nothing. And I'm pretty sure when I get it back together it'll still be that way but it'll also be easier to disassemble this if I need to do it again. I'm not real sure what the weight does it counterbalances what exactly the pump running being interesting to see everything working without the weight I think it would be fine
     
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