Red triangle, TCS, (!), ABS, VSC, CEL after parking

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by jenesuispasbavard, May 7, 2021.

  1. jenesuispasbavard

    jenesuispasbavard Junior Member

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    So, it's been about 800 mi since the last service on my 186,884-mile 2008 Prius.

    After the last service which included a 'rear brake job' to replace the rear brake pads / shoes, the car has been unreliable with its parking brake - I asked earlier this week to take it back in but no response so far; I'll just take it back in next week anyway.

    Yesterday I parked on a slight slope for the first time since the service, and it turns out the parking brake no longer works as well as it did – the car stopped because it was in park, not because of the parking brake. Tested it in neutral and it rolled on the slope on its own; and engaging the parking brake when stationary the car still rolled, just more slowly.

    Not sure if this is a related issue, but today I got the lights described in the title, a red car icon on the screen, and the car won't turn back on (power light stays orange even with brake pressed). This first happened after I parked but before I turned off the car.

    Picture attached.

    Any ideas? And any relation to the parking brake issue?

    Generic OBDLink LX OBD-II device shows no error codes with the Carista app or its own OBDLink app, but I know some codes are Prius-exclusive.
     

    Attached Files:

  2. ChapmanF

    ChapmanF Senior Member

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    If it's a Gen 2, it has rear shoes, and the adjustment is mechanical. Loose parking brake is usually because of loose adjustment back at the shoes (resist the temptation to crank the adjusting nuts on the parking cable; that's virtually never what's called for).

    If the adjusters aren't waay too loose, you can catch them up easily with the car sitting still, just repeating (apply and release parking brake, apply and release foot brake) in alternation, as described more fully here. If the adjusters are working right, each pair (one apply-release of parking brake followed by one apply-release of foot brake) will take 0.03 mm out of the shoe-to-drum clearance, and you'll eventually get to where the parking brake has the right number of clicks of travel and the right ability to hold the car.

    If you feel like you're tired of doing that and it's not improving, it can be worth taking the drums off and watching while a friend does that; you can watch the adjust lever click up over the starwheel tooth when the parking brake is applied, and turn the starwheel down one tooth when the foot brake is applied. (That's an advantage over the other kind of rear-drum adjusters that work by driving in reverse; the car doesn't have to move for these to work, so they're super easy to watch in action.)

    Sometimes you will spot a problem, like the starwheel is just stuck, or has a tooth that is rounded off because the lever has been slipping over it. The parts are cheap if they're worn out. There's also a way you can hurry up the adjustment using a pry tool through the rubber plug in the backing plate, but I've rarely bothered.

    Also, the adjusters are distinct left and right; if they got swapped, they either won't turn (because the cut of the teeth faces the wrong way) or if they do turn they will be "auto-loosening" which is never what you want.

    You might also be interested in finding out what the warning lights are on about. If you don't have a code reader that can tell you, there are threads here describing how to use a jumper wire and count light blinks to get two-digit versions of the trouble codes. It's less detail than you'd get from a proper reader, but it's better than guessing, and saves you from having everything hanging on finding a reader that will work.
     
    #2 ChapmanF, May 7, 2021
    Last edited: May 7, 2021
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  3. jenesuispasbavard

    jenesuispasbavard Junior Member

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    Thanks! I'll give your one-two system a shot for the parking brake and see if that works.

    Another bit of information - the parking brake isn't completely smooth all the way to the bottom. It used to get harder to push about halfway down (this is how I knew it was engaged), but now it just goes all the way down - but it still does the clicks on its way down.

    Does the combination of dash lights indicate a specific problem? I don't have a Prius-specific code reader unfortunately. Just wondering if the rolling-while-parking-brake-engaged and dash lights are connected.
     
  4. ChapmanF

    ChapmanF Senior Member

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    I don't think there are trouble codes specific to the parking brake. So the codes you have are probably not connected to that. On the other hand, they are still codes and worth retrieving, because they may tell you something else worth knowing about your car that you wouldn't know otherwise.

    Your description of how the parking brake feels is consistent with the shoes just being badly adjusted. The ratchet that clicks is built into the pedal; it will always click. Pushing it all the way down before it feels tight just tells you there's too much clearance.

    If you don't notice it starting to get tight (beginning toward the very bottom of its travel, of course) after a bunch of one-twos, it'll be time to have a look-see behind the brake drums.

    With the adjustment off back there, it will also take excessive brake fluid to apply the regular brake. That system is brake-by-wire so it is able to compensate, but it might set codes about it. That's one way the codes could be connected. (It's also possible such a code could lead the ECU to say "might be a leak back there, I'm going to stop sending fluid", which would then frustrate you in the one-two exercise, because you'd have no way to 'two'. In that case you'd have to try to get the adjustment closer to begin with, put stuff back together, and clear the codes. You should jot down what the codes are before clearing them.)
     
    #4 ChapmanF, May 8, 2021
    Last edited: May 8, 2021
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  5. jenesuispasbavard

    jenesuispasbavard Junior Member

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    RIP, lots of errors: P0AA6, C1259, and C1310 after the 12V battery was replaced. Before replacement, it also showed C2121, C2122, C2124, C2318, B1421, and B1400...

    Looks like the HV battery is on its way out, or gone already. Thankfully I'm in Houston this weekend and Hometown Hybrids is available tomorrow to check it out / replace the battery.

    The one-two alternating pushes on the brake / parking brake didn't help, sadly. The force needed to push the parking brake remains pretty low.
     
  6. jonsey1886

    jonsey1886 New Member

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    Toyota dealership tech here-P0AA6 has 5 different sub-codes called information codes. And can be set by something as simple as missing/damaged/deteriorated frame wire grounds, forgetting to plug in one or more of 3 plugs attached near the positive end of the 12V battery (2 plug into the fusible link block mounted on the positive terminal clamp, 1 plugs into the EBC battery backup), melted fusible link(s) in the fusible link block, using a regular (flooded lead acid) battery instead of the Valve Regulated AGM battery required, having a completely flat 12V battery or someone played with the giant orange service plug and didn't reinstall it correctly.

    Information codes are: 526, 611, 612, 613, and 614. 526 is a general information code which goes away after the HV Battery ECM determines where the fault is and one of the 61x codes sets in place of it.

    C1259/58-HV System Regenerative Malfunction C1259/59 is stored if the power switch is ON (READY) with the HV battery service plug disconnected.

    C1310/51-Malfunction in HV system

    Start by checking that all the connectors I listed above by the 12V battery are indeed plugged in correctly and the giant orange service plug ensuring it is properly inserted and latched.
     
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  7. jenesuispasbavard

    jenesuispasbavard Junior Member

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    Unfortunately I'm not nearly as handy as some of y'all, so I just called Hometown Hybrids while I was still in Houston. They came by and confirmed that it was the HV battery (code P0AA6 with 526 and 612), and replaced it with a rebuilt battery for $1000.

    If I hadn't been 'stranded' in Houston that weekend I might've considered diagnosing and trying to fix it myself over the last week, but this was a quicker solution and it comes with a 2-yr / 50000-mile. With the car already at 189,900 miles I didn't feel like shelling out $2300 for a new battery, so hopefully this one will suffice for the foreseeable future!
     
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  8. bisco

    bisco cookie crumbler

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    great people
     
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