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Inverter coolant changed - now ABS failed.

Discussion in 'Gen 2 Prius Care, Maintenance and Troubleshooting' started by kkeane, May 14, 2015.

  1. kkeane

    kkeane Junior Member

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    A few days ago, I took my 2005 Prius to the Toyota dealer to have the inverter coolant changed, long overdue maintenance. They did their usual walkaround check, and didn't find a problem. I had never been to this particular dealership before (the only reason I went this time was logistics - their shop is within walking distance of my work), but there were a few red flags that makes me suspect their quality of work may not be perfect. For one, they did the usual checklist-inspection and missed some very obvious problems, such as a broken taillight. They also quoted me a price dramatically higher than other dealers in town. When I mentioned that another dealer quoted me $160 for the same job they were asking $250 for, they magically pulled a special promotion out of their hat.

    They also took care of a recall item (some steering mechanism issue) while the car was in.

    When I took the car home, within 6 hours and 70 miles of picking it up, the brake, (!), ABS and VSC lights came on solid. Brakes are working fine, thankfully, but the ABS does not kick in. I can do the reset routine (put the car into READY, tap the brake pedal eight times, then turn the car off). This will turn off the lights, but they come back on as soon as I tap the brake.

    I already checked the four ABS fuses, and they seem good.

    Is there any other DYI troubleshooting I can try before taking it back to the dealer?

    Also, the timing of the problem is suspicious. Are there any ABS components near the inverter coolant system or the steering mechanism that could have gotten damaged? Or is this unlikely, and the timing was mere coincidence? My Prius is pretty high in miles, so problems are expected from time to time.

    Since I haven't established trust with the dealer, I'd rather walk in knowing as much as I can, rather than either being at their mercy, or - possibly falsely - accusing them of having caused the problem.
     
    #1 kkeane, May 14, 2015
    Last edited: May 14, 2015
  2. Mylar

    Mylar Member

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    I'd reset the ABS lights using the paper clip method and see if it goes back on. There is a link to this on Prius Chat.
     
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  3. JC91006

    JC91006 Senior Member

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    Check and make sure the voltage on your 12v battery is acceptable. Maybe the service tech left your door open and drained the battery.

    If the battery is not the problem, then you would have to bring it back to them to figure out the issue. Probably got some air in the system while he changed the coolant.
     
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  4. Mylar

    Mylar Member

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  5. kkeane

    kkeane Junior Member

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    Thanks for the tips! It seems to me that the lights do indicate a real problem; the ABS is not kicking in, after all.

    Would the reset methods just reset the lights, or also reset the ABS and bring it back to work?

    I had read about the voltage issue before, but because the ABS isn't working, didn't think that was the problem. Would that possibly also cause the ABS to fail?

    In that case, the problem is likely my traction battery, rather than the 12V battery. I already knew that it was dying a slow death. It is spending a *lot* of time at a single bar (no dashboard lights or codes from the battery, though, so the Prius still thinks the battery is good), and I drive up a 4000 ft mountain every day. When the problem first appeared, I had just reached the peak of the mountain. That may well have depleted the 12V battery, too.
     
  6. JC91006

    JC91006 Senior Member

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    If your car is under 150k miles, your hv battery would still be under warranty in CA
     
  7. kkeane

    kkeane Junior Member

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    Unfortunately, I'm at twice that mileage :-( Also, if I remember right, the CA warranty for the battery is actually 150,000 miles or 10 years, which means that for a 2005 Prius, it's over either way.
     
  8. JC91006

    JC91006 Senior Member

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    best you get the DTC codes read, no guessing
     
  9. kkeane

    kkeane Junior Member

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    The 12V battery seems good; I just measured the voltage at 12.48V
     
  10. kkeane

    kkeane Junior Member

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    I already checked the DTC codes; there are none. Or are there some DTC codes my reader would ignore? I have a low-end $40 reader.
     
  11. JC91006

    JC91006 Senior Member

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    You need a reader that's capable of reading Prius codes. Mini VCI is good to get, it's around $25 on Amazon and runs off a Windows laptop with 32bit OS
     
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  12. northwichita

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    Does the reservoir for the inverter coolant have turbulence when the car is in READY mode? This would be my first step, making sure the coolant change was done correctly.
     
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  13. kkeane

    kkeane Junior Member

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    Nope, no turbulence that I could see. It's kind of hard to tell because I'm not sure exactly what to look for, but it looked perfectly smooth (I did take off the cap, of course). When the ICE kicks in, of course the little ripple waves that you would expect from vibration, but I don't think that is what you were talking about.
     
  14. kkeane

    kkeane Junior Member

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    Thanks for the tip! I'll order one of the Mini VCIs soon. 32-bit laptops are getting rare, but after some Googling, it looks like the newer versions also work on 64 bit.
     
  15. ChapmanF

    ChapmanF Senior Member

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    While the car is IG-ON the inverter pump should be running, and what you see might or might not be what you call 'turbulence', but the front end of the reservoir (where the return hose attaches) should have a visibly higher liquid level than the rest of the reservoir, whereas with ig off it should all find one level that way liquids do.

    You can find posts (mostly in the Gen 1 forum probably) about how to read brake codes without a special reader, by jumpering two pins (Tc and CG) at the diagnostic connector and counting light blinks on the dash. For years I wasn't sure if that still also worked in Gen 2 (don't have one myself to test), but recently saw in another post that it still even works in Gen 3!

    -Chap
     
  16. kkeane

    kkeane Junior Member

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    I was able to read the blink codes with the jumper method. So, yes,it works in Gen II. The codes I read are 35 for the (!) light, 42 for ABS and 45 for VSC. Haven't found a list of the meaning of these codes yet.
     
  17. kkeane

    kkeane Junior Member

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    As for the inverter coolant: it is hard to say because when off, the coolant level is right at the seam of the tank. When I turn the engine on, it looks like the *rear* level is slightly higher.
     
  18. Patrick Wong

    Patrick Wong DIY Enthusiast

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    Apparently there remains air in the inverter coolant system. You can either return the car to the dealer to have the job re-done, or you can do it yourself.

    The reason the skid control ECU is logging DTC and the various brake system warning lights are coming on is because the 12V bus voltage is too low. The voltage is too low because the inverter is overheating due to lack of coolant flow, and the DC/DC converter has shut down.

    To purge the inverter coolant system yourself, you need a gallon of Toyota Super Long Life Coolant and a length of clear vinyl hose whose inner diameter will fit the inverter coolant bleed valve.

    Remove the large black plastic cover over the radiator. Then you can find the bleed valve for the inverter, in front of the inverter. Run a clear vinyl hose from the bleed valve up to the inverter coolant reservoir (remove the reservoir cap so the hose can be inserted in the reservoir.)

    Open the bleed valve and fill the coolant to the full mark in the reservoir. You should see fluid rising in the vinyl hose and ideally it will get to the same level as the reservoir coolant level. Then close the bleed valve.

    Make the Prius IG-ON for 20 seconds, then IG-OFF. Open the bleed valve and let the air out. Close the valve, refill coolant in the reservoir as needed. Make the Prius IG-ON again for 20 seconds, then IG-OFF. Open the bleed valve, etc. and continue that process until air no longer appears, you see turbulence in the coolant reservoir, and the inverter coolant pump quiets down and sounds like it is pumping fluid and not just air. This process is actually easier to perform than it sounds.
     
    #18 Patrick Wong, May 14, 2015
    Last edited: May 14, 2015
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  19. kkeane

    kkeane Junior Member

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    Thank you so much. I had wondered why northwichita was asking about the inverter coolant, what the connection to the ABS might be. Thanks for explaining it!

    That said, a couple questions:

    - After I clear the ABS codes, with a cold engine they come back immediately as soon as I tap the brake. At that point, the inverter wouldn't have had time to overheat yet, would it?
    - When it's pumping air, doesn't the coolant pump produce a whirring sound, similar to how a slipping V belt would sound (on cars that have them)? *Before* I took the car for the inverter coolant change, I did hear that sound once or twice a few weeks ago (which was the reminder I needed to finally get the inverter coolant changed in the first place), but I did not hear that sound after I got the car back.
    - Wouldn't the DC/DC converter shutting down also cause DTC codes from the ECU, or some other symptoms?
     
  20. dolj

    dolj Senior Member

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    It could be coincidental, in that when you put your foot on the brake, the addition of the brake lights drawing their current is enough to put the 12 V bus into a low power situation and there by trigger "ghost" trouble codes. You could validate this theory by connecting a DVM to the 12 V bus and watching the voltage as you do various processes.
     
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