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ABS warning lights

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by PhilWray, Jun 3, 2018.

  1. ChapmanF

    ChapmanF Senior Member

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    It seems to me among the threads on PriusChat that I've read myself, I have seen that happen, and it left me at a loss to explain it, but that happened only in one or two threads that I recall seeing.

    On the other side of the balance, there are already at least that many threads where I have been able to steer people directly to a resolution based on the blink codes they posted, and that has been my personal experience when I pull my own codes, too.

    In between those extremes, there have been cases where weird codes were reported and, on closer comparison to the ones in the manual, it was clear the poster had just been one digit off when counting the blinks (e.g. 12 34 56 => 23 45 61), and that's not too difficult to clear up. And cases where codes were googled and found on the web in non-Prius-specific documents; people do that with the five-character DTCs too.

    In the one or two threads where I was not able to find or explain the codes with the manual, I suspect there may have been a mistake or omission in the manual. In my experience those are very rare, but examples can be found. One Gen 1 body ECU code that baffled me for the longest time turned out to be, once I understood it, a probable Japanese-English translator's confusion between 'stop' and 'lock'.

    To check the battery voltage is the default response of so many other posters here that it will live on just fine despite not being mine. In my experience, low battery voltage might be causing "spurious" codes if it is low enough that your headlights slowly rise to an orange glow. That condition can be recognized without a voltmeter. Above that threshold, my experience has quite reliably been that the codes mean what the manual says they mean. There's time for alternative explanations in those cases where codes are retrieved and not found in the manual, but one isn't in that case until one has at least, for starters, retrieved the codes.

    -Chap
     
  2. dolj

    dolj Senior Member

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    You will need to clear them. Most codes are cleared when you disconnect the 12 V supply, but not ABS/TRAC/VSC codes.

    For the 12 V battery to be the problem, you will have to prove it drops under 10 V when driving. Even if you do prove that, it does not mean the 12 V battery is the problem, merely the victim of something else. Just don't think you should spend good money chasing a hope that replacing the 12 V will fix the problem. It only will if you can see that the battery has a dead or shorted cell. Most time just blindly replacing the 12 V battery does not fix the problem. Sometimes the 12 V battery is collateral damage and needs to be replaced because it got damaged, even though it was not the cause of the problem. I hope that doesn't sound contradictory, just trying to highlight it is not as simple and straight forward as some make out it to be.
     
  3. PhilWray

    PhilWray Member

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    I'm sure I got the numbers correct but I'll reread the codes later tonight just to be sure.

    Thanks,

    Phil
     
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  4. ChapmanF

    ChapmanF Senior Member

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    One quick note I'll add: there are some number of trouble codes (like the C1241 shown in post #17) that have words like "low battery positive voltage" in their fortune cookies. It's important to remember that these are talking about the measured B+ voltage at a specific input terminal of the ECU giving the code. The "detection condition" (in contrast to "detection item") shown at the start of the code's workup pages in the manual will give the details.

    Such codes, especially combined with other codes suggesting intermittent or open circuits, are at least as likely to turn out to involve flaky connections or wiring somewhere between that ECU and the battery, as to implicate the battery itself.

    -Chap
     
  5. PhilWray

    PhilWray Member

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    Hi All,

    Thanks for all your input.

    ABS relay & Break stop switch replaced over the weekend - all good so far.

    Regards,

    Phil
     
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  6. PhilWray2

    PhilWray2 Junior Member

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    Hi All, Just to note I have had to Re-Register as PhilWray2
     
  7. RP67

    RP67 New Member

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    Hi is this problem fixed permanently with the relay and brake switch? I have the same problem but I have to go through on quite a few things. I just purchased recently this car and I had multiple problems. It appears to be this is the last one.
    Cheers
     
  8. ChapmanF

    ChapmanF Senior Member

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    What trouble codes are you showing? Is there any reason to think you have the same problem as the person who started this thread?
     
  9. RP67

    RP67 New Member

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    Well, apparently I just waiting for my Techstream what I bought to sort out a few problems on my "new" car, apparently I had a faulty inverter water pump, and a broken wire on the battery ECU, what I repaired already. As far I know no brake related repairs has been done on the car recently. I might need to check the brake-pads.... I have Torque Pro with the relevant pid-s but I have no codes on that. I presume Torque isn't the correct tool to get ABS faults identified. Apart from the lights, the car drives normal, even the traction control works as it should. That's why I presume this problem is something simple.
     
  10. ChapmanF

    ChapmanF Senior Member

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    Warnings are usually given when the car "drives normal" and before you've outwardly noticed problems. If they weren't, they'd be less like warnings and more like weather ropes.

    While you're waiting for the Techstream rig, there is a way to retrieve basic codes from the brake system by jumpering the Tc and CG terminals at the diagnostic connector with a wire, and counting some light blinks.
     
  11. RP67

    RP67 New Member

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    Ok, I did not considered doing that, but apparently that is another option. I start to research about the "blink code". This is the two terminal what I should use to resetting isn't it?
     
  12. dolj

    dolj Senior Member

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    I don't know if it is the same ones you use to reset, but these are the two to which Chap is referring:
    Prius OBD2 port.jpg
     
  13. RP67

    RP67 New Member

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    Great, I have
    ABS 42
    (!) 53 59 94
    I searching....
     
  14. ChapmanF

    ChapmanF Senior Member

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    Well, then we run into the occasional situation where the blink codes are not as well documented in the repair manual as the full five-character DTCs.

    The 53 on the ECB light seems to be a complaint (C1253) about the relays that power the hydraulic pump. When Techstream arrives, you'll be able to pull an additional INF code that helps sort the situation into one of seven possibilities. There are eight pages in the repair manual for working up that code.

    The 59 I'm not sure about; it appears some places in the manual as the blinky form of C1259, but in other places, 58 is given instead. In any case, C1259 is just a code the brake ECU sets to advise you of a problem being reported by the HV ECU. The rest of the story has to be gotten from the HV ECU, which has no blink codes, so can only be interrogated with Techstream.

    94 might be a network communication problem, U0073, on the CAN bus.

    I have not found 42 listed as an ABS light code. There is a 42 listed as an ECB light code, but one can't be sure that means anything; the codes are segregated by which light blinks them out.

    The 42 on the ECB light (which might be completely irrelevant here) would be an issue with the two incoming power supply circuits to the ABS system. Techstream would pull up an additional INF code, 87 or 88.

    The two incoming power circuits, IG1 and IG2, are controlled by the ABS no. 1 and ABS no. 2 relays, respectively. They are meant to turn on and off together. The C1242 INF 87 would mean there was some period of four seconds or longer where IG2 had power and IG1 did not, and INF 88 would mean vice versa.

    But again, that's supposed to be 42 blinked on a different light, so I could be completely off track.

    Sometimes, when these mystery blink codes come up, it would be very interesting to see what actual 5-character DTCs you get when you have access to Techstream, and might help to flesh out the fragmentary blink code info that's in the manual.

    Problems with sequencing power-up might have been recorded at one point if someone tried to power up the car when the 12 volt battery was crazy low on charge (that is, not tenths-of-a-volt low, but lights-glow-orange, brake-pump-sounds-like-a-dying-bagpipe low). If that could have happened, a good long encounter with a charger could help.
     
    #34 ChapmanF, Aug 13, 2019
    Last edited: Aug 13, 2019
  15. RP67

    RP67 New Member

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    Thanks for that, I guess nothing much to do just now.
    Here is what I seen in case I miscounted
     
  16. dolj

    dolj Senior Member

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    42 is not listed as a ABS code, but a ECB one.
    53 = C1253 – Hydro Booster Pump Motor Relay Malfunction

    59 = C1259 – is stored if the power switch is ON (READY) with the HV battery service plug disconnected.
    Prius Saftey Interlock.jpg
    Make sure the third step was performed correctly when (if) reinstating the HV battery service plug.

    Couldn't find a 94. Could it have been 95?

    95 = C1203 – ECM Communication Circuit Malfunction

    Or something else.
     
    #36 dolj, Aug 13, 2019
    Last edited: Aug 13, 2019
  17. RP67

    RP67 New Member

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    Thanks dolj, it seems to be 94. I focus on fuses, relays and cable for now. Hopefully Techstream be here before the weekend...
     
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  18. RP67

    RP67 New Member

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    So an update on my ABS light situation. Techstream (VXDIAG apparently with Techstream) has arrived yesterday as a clockwork.
    I spent a couple of hours to try the unofficial version to run and ended up to buy 2 days worth of TIS subscription. I found a whole bunch of fault as you can see on the first picture, then I tried to reset them one by one.

    I managed to clear all of them, apart from C1253. It appeared to be gone but by the time i refreshed the screan (did a health check) it came back. So I started to do the physical inspection as per service manual..... long way to go. Anyway I finally went to the "Urility" page then I erased "learned" data from the ASB/VSC/TRAC ecu and run a brake initialization (if I remember the name correctly) which I already tried with a paperclip, but that wasn't successful. After that, all the lights gone, no faults are back yet.
    20190816_181726.jpg 20190817_080233.jpg

    I really appreciate all your support so far I hope someone could use my addition with success. Sorry it isn't the "McGyver" way what I would prefer but eventually lead me to sort these issues out.
    I still have some open questions regarding Techstream, like how can I get the inf codes etc. but at this point I'm quite happy with the result.
     
  19. ChapmanF

    ChapmanF Senior Member

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    The little snowflake icons (you can see them next to two of your codes) will show you records of lots of measurements saved at the instant the code was set (snowflake, "freeze frame", get it?). INF codes will be in there.

    More generically, C1259 gets set in the brake ECU whenever it gets a message of any abnormal condition from the HV ECU. It could be the service plug, or any of the other conditions the HV ECU can report. So a C1259 really means "hey, go read codes from the HV ECU."
     
  20. RP67

    RP67 New Member

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    Yes, I guess I set C1259 when I had the HV fuse out.... Anyway I briefly checked the snowflake thingy (that make sense now...), but being ignorant I just skipped that. Great to learn things, my learning curve is pretty shallow, like the graph on my avatar. Thanks Chap.