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New codes after ABS Actuator replacement

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by cjn486, Jan 13, 2024.

  1. cjn486

    cjn486 Junior Member

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    Codes shown from techstream are:
    P0AA6, C1246, B1421

    99% sure these codes were not present when I first was having the ABS lights indicting i needed a new actuator.

    Any help would be greatly appreciated.
     
  2. Tombukt2

    Tombukt2 Senior Member

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    This is the battery isolation fault code so you have the orange safety plug out I'm assuming it's been reinstalled but on the last step of the insulation where you push the handle down sometimes you have this very smartly push that handle down to lock into the last step Do you in fact have good connection and when you push the brake and the button your car is readying? Clear the codes and try again that's first thing you want to do and then if you're P0AA6 code returns then you'll need to get a scanner that will get you the subcode which if you look in the freeze frame data on some decent scanners you may see a subcode like 521 or 614 or 612 you need one of these three codes I believe to narrow down your leak area usually it's back in the battery area but I'm going to say that and then yours will be up in the inverter area so this is why you need the subcode to narrow it down to the three areas of the car where this generally happens.
     
  3. cjn486

    cjn486 Junior Member

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    I have a copy of techstream which is how I got the codes originally.

    Any idea how I can use text stream to get the subcodes?
     
  4. ChapmanF

    ChapmanF Senior Member

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    In the freeze frames saved for the codes, which you get to by clicking the snowflake (get it?) next to a code.
     
  5. Tombukt2

    Tombukt2 Senior Member

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    Usually when I click on the snowflake in my Toyota version of tech it used to show the code right up next to the main code and the big letters on top of the freeze frame screen but I've noticed in the last few weeks I don't know what's changed when I click on the snowflake I have to scroll down into the small text and down in there it will show me the original code and then codes with three digit subcodes underneath that It's hard for me to post pictures here all that resizing and nonsense but it's in down in the smaller text you'll see like a 612 or a 613 or a five something code I believe the first one is the main one and the second one is the second place to look and so on and so forth usually this problem for most people works out to be in the battery silver case in the trunk area and some instances folks have had a bad orange wire running from the battery to the inverter which is another sub code and then some have actually had a problem up in the inverter area which is under the hood all of that is discussed here on Prius chat quite a few posts All of my problems personally have been in the battery case I have had no failed wires and the silver inverters and a generation 2 are almost bulletproof Don't shoot it to find out but they are stout after 2009 possibly not so much.
     
  6. dolj

    dolj Senior Member

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    Nothing has changed. It can display differently depending on the DTC you're looking at.
     
  7. Tombukt2

    Tombukt2 Senior Member

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    Yes I understand that's confusing If I had my laptop open and a way to run a video and all I might could show it but it's not important. It's just that when I first used tech or maybe only certain codes when they come up in tech sometimes we'll show the subcode right next to the main code right up there in the very top on the big bold letters or it did the first couple of times I used tech then when I had the problem with the battery isolation fault I noticed this wasn't working that way had to look down in the small text down in the data way down the list like 14 columns and their sits the subcodes I'll have to take a picture of it next time I do it but I didn't have to do that on some other codes that I had using the same tech CF-13 computer and the same version of the dealer software that I've never changed or altered but anyway is no matter it's just a good look across the text and you'll find the sub codes buried down in the little tiny text You just have to look for them If you don't know they're there you might skip right over them.
     
  8. cjn486

    cjn486 Junior Member

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    Alright, it has been a couple of months, and strangely some codes have gone away and others popped up. My current codes are now the following:

    Car seems to run just fine, and I have great stopping power but "ABS" "Brake Light" and "!" are showing on dash. When I start the car they are not present until it goes into drive or reverse.

    C1253, Hydro- Booster Pump Motor Relay
    C2300 - Actuator System Malfunction
    C2318 - Low Voltage Error (Power Supply Malfunction)
    B1421.

    ( Clicked on the snowflake on many of these but didnt see any subcodes. Took pictures of all the data. I have a laptop with techstream to diagnose.)

    Additionally I notice while monitoring techstream while driving that the "FR Regenerative Request" was not responding when braking only continually showing 0 while FL was showing live data while braking, accelerating etc.

    Wheel speed sensors on all 4 wheels were responding as well.

    Any help on where to start would be great.
     
  9. Patrick Wong

    Patrick Wong DIY Enthusiast

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    C1253 points to a problem with the ABS MTR or ABS MTR2 relays, the wiring harness or the brake actuator assembly. I understand you have already replaced the latter.
    C2318 points to a problem with low voltage which might be caused by a defective relay.
    Ignore B1421 as that relates to the air conditioner system, solar sensor.

    You could test the relays by removing one at a time, when the car is IG-OFF. Use an ohmmeter to find the relay coil terminals, it should show a resistance of around 10 - 20 ohms. Apply 12VDC to the coil terminals. Then use the ohmmeter to measure resistance across the switched terminals which should be 0.5 ohm or less after you account for resistance in the test leads.

    Make sure that the 12V battery is in good condition and that the connectors are tight. Measure voltage across the battery. A new, fully charged 12V AGM battery will measure 12.9V after the car has been sitting overnight resting. To the extent that the actual voltage is below that, you will have a sense of how discharged the battery is.

    After you've made all of the above checks, if the DTC still persist, see if you can clear them. C2300 might not clear; if so you would have to remove the P CON MAIN fuse for 60 seconds or more, then reinstall it. Or, remove the negative 12V battery terminal cable for that period of time, then reconnect it.
     
  10. cjn486

    cjn486 Junior Member

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    Thanks so much for the response back.

    I tested four of the ABS relays which were all the ones I could locate.

    They all with an audible. Click click on when I applied 12 volts from the battery.

    With the 12 volt still attached on the two parallel leads I checked the ohm on the other terminals And got a positive beep showing continuity on all 4 units.

    My battery testing over a couple of different days reads 12.5 volts I just replaced my 12-volt battery about 6 months ago thinking it was the problem.

    On a side note
    Additionally while the hood was open of the Prius as I was getting my gear ready for testing I did hear what I thought to be a relay click. Unsure if that is normal after some time. Maybe from opening the driver side door and popping the hood? It's on a timer maybe?

    Wanted to check back here before I removed the codes via text stream or the Main Fuse.

    Let me know if you have any additional things to try.
     
    #10 cjn486, Apr 22, 2024
    Last edited: Apr 22, 2024
  11. dolj

    dolj Senior Member

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    Clear them with Techstream, but before you do, save the session file so you can look at it later if you need to. It should offer the option to save the session when you go to exit the session.
     
  12. cjn486

    cjn486 Junior Member

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    Got into the car this morning no lights were on on the dash, but codes were still internally present.

    I pressed down and held down the brakes , heard the brake actuator clicking noises turn on working while brake was depressed, then soon the "!" ABS and the brake light came on.

    After clearing the codes, drove a little bit. The lights went off on the dash. When stopping at a stoplight the Brake ! And ABS lights came on and the 2 following codes were found in the system.

    C1246 - Master Cylinder Pressure Sensor
    C1253 - hydro booster pump motor relay

    Any help with what to check next?
     
    #12 cjn486, Apr 23, 2024
    Last edited: Apr 23, 2024
  13. mr_guy_mann

    mr_guy_mann Senior Member

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    I would think you might want to look up the diagnostic procedure for that code in the factory service manual.

    Possibly look at what the (2) master cylinder pressure sensor readings are - both when foot off the pedal then while pressing down.

    What bleeding procedure was done when the actuator was replaced?

    Posted via the PriusChat mobile app.
     
  14. cjn486

    cjn486 Junior Member

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    I tried the bleeding procedure without techstream that I did not have much success with. So then I went and got a copy of techstream and tried to follow all the protocols and it wasn't as straightforward as the videos or text threads indicated.

    So I have had a suspicion that maybe I should just go and try to have the brakes re-bleed at a dealership thinking maybe I didn't do it the right way. But we followed all the techstream instructions and me and another individual did it multiple times but it didn't seem like a very straightforward process as I would have thought it to be.
     
  15. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Regarding the relays, I suggest that instead of relying upon the continuity test (which is go / no-go and it is not clear how much resistance is allowable for a go reading), that you measure the actual resistance of the switched contacts. First, set your digital multimeter to the ohmmeter position, and short the test leads. See what the reading is - for example, it might be 0.3 ohms. Then subtract that reading from the readings you take when you measure the relay switched contacts resistance so that you have the actual measurement of the relay resistance.

    If that test doesn't point to a relay failure, then maybe it is time to have your local dealer investigate and give you their recommendations. Good luck.