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Can't start my 2011 Lexus ct200h, 'check hybrid system'

Discussion in 'Gen 3 Prius Care, Maintenance & Troubleshooting' started by jaholmes, Jul 9, 2024.

  1. jaholmes

    jaholmes New Member

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    Hello,
    I have read hundreds of threads in this forum, and others including the ct200h forum, and tried every suggestion I have seen and everything I can of, multiple times over 3 days, but nothing changes.
    Problem:
    When trying to start the car, green light is on on the start button, hit the start button and the ready light flickers for about half a second, and then all instrument panel lights are on similar to if you turned it to 'Ignition On' mode by not pressing the brake pedal. When I reset everything by disconnecting 12 volt battery, disconnecting white wire, unplugging Orange safety plug, and waiting 15 minutes, and then try starting, the ready light comes on and stays on for 20 seconds or so and then it goes back to the same state. The gas engine never runs. I have taken the cover off the hybrid pack and checked voltage, which is 201.1V. I checked all groups of 2 cells, and the lowest measure 14.1V.
    It occurs to me that it might be dying and ready light going off right when it tries to turn over the gas engine. Could it be that the hybrid battery doesn't have enough juice to turn the engine over, or is something else wrong? Also, there is some corrosion on bolts of each bus connection (as seen in attached picture), but maybe that is normal for a 14 year old car.
    Background:
    Car was running rough last fall, so it sat for the last 8 months. I removed the intake to clean egr passages and changed the plugs. Now car won't start. I double checked and triple checked all connections. I replaced 12v battery with new. Trickle charged both batteries to 100%. Tried jump box and jumping with other vehicle. All lights come on instrument panel. Light on start button is green. But car won't start. Get message to check hybrid system. Hybrid battery graphic shows only one bar.
    There are no codes related to the hybrid battery. Current codes are B126a, U0100, B2312. The hybrid battery worked great when it last ran.
    Thank You
     

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  2. bisco

    bisco cookie crumbler

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  3. jaholmes

    jaholmes New Member

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    Screenshot_20240803-193659.png Screenshot_20240803-210812.png
    I had to go out of town for a couple weeks, and then I waited for a new obdii scanner to show up, so I finally just got back to the car today.
    Thank you for the response, bisco. I can't find any damaged wires, but I haven't dug into everywhere.
    I tried a third new 12V battery, and a fourth large deep cycle battery. Nothing changes with either. It seems the ready light might stay on a bit longer with the large battery, but it might just be my imagination. Regardless, the gas engine never turns over.
    I used the DrPrius app and the Hybrid Assistant app, but I'm not sure I know anymore than I did before. It definitely looks like a couple cells are worse than the others (matches what I saw with the multimeter). As you can see in the images, after an hour and a half of messing with it, the pack voltage dropped 7 volts. I did get code p0a0d occaisionally, but not always, and no other codes.
    If there were a damaged wire, would you see any of these results? If the inverter was bad, would you see any of these results?
    Any ideas?
     

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  4. bisco

    bisco cookie crumbler

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    autel maxi 200 is supposed to be a good scanner. did you clean up the battery corrosion?

    if it's the hybrid battery, you should get the P0A80
     
  5. Eddie25

    Eddie25 Active Member

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    Do things work in ON mode? Do the windows work? Have you reset codes to see what comes back?

    The U0100 being a CAN communication code, from what I can tell, I'd be most interested in that. I'd do CAN resistance checks and CAN to ground checks (making sure the car is asleep for those). If you had a scope you could just look at the CAN signal. My professional Youtube video watching knowledge is making me think you could have a bad module that is compromising the CAN network, assuming no rodent damage.

    The B2312 being a power window malfunction would have me disconnecting the power window ECU, which I think is the "Multiplex network master switch assembly" which I think is just the main unit on the driver side door (so it might be pretty easy to unplug and be a quick hail mary). I could be wrong about all that though.

    Does the B126a have a description?
     
  6. jaholmes

    jaholmes New Member

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    I got a Carista EVO which my research showed was a good scanner for these cars. I was previously using a Bluedriver, which I believe is great overall, but doesn't work with Dr. Prius and such apps.
    I did not clean the corrosion.
    I believe everything works in On mode, but I will confirm again. When I clear the code, it comes back in about 1 second.
    The B2312 and B126a were set when I very first scanned the car about 6 weeks ago, with the Bluedriver and before changing the 12V battery. They have never returned since clearing the codes back then. However, at this point I will try just about anything, so I think I will disconnecting the harness to the door just to see what happens.
     
  7. Mendel Leisk

    Mendel Leisk Senior Member

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    Those dr prius voltages per block don't look good.
     
  8. jaholmes

    jaholmes New Member

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    After reading much about obd scanners causing U0100 errors and cars not running, I tried disconnecting the scanner and clearing everything by pulling orange plug, white wire in fuse block, and disconnecting 12V for 20 minutes. When I tried starting the car, it was definitely different. Exclamation point and 'check hybrid...' message was still there entire time, ready light came on about 10 seconds after Start button was pushed. After a few seconds, I tried to get the engine to turn over by hold break in and pushing throttle. The instant I touched the gas pedal, ready went off, all other warning lights came on, and car seemed to jerk a bit. I then plugged scanner back in thinking there should be new codes set, but there was again, only the U0100 code. All the block voltages and such seemed about the same after this experiment.
    Do I need to find a third scanner in hopes of finding one that does not cause CAN issues?
    Asked before, but is it possible the hybrid battery is just not producing enough amperage to kick the IC engine in? With 200+V? But wouldn't that post some other code?
    As far as the poor voltages on some of the blocks, I feel that it is mostly only because the car has sat so long, and if I could get it running, it would charge them up. I would be happy to buy a grid charger, if I knew the car would eventually run, but If I can't figure this out soon, I will probably just part the car out, so I don't want to waste the money without knowing.