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U0100 code

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by jim11132, Jun 19, 2024.

  1. jim11132

    jim11132 New Member

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    Hello: I recently replaced the headgasket, timing chain, etc. on my v. That seems to be the simple part. The engine will not start (starter does not even engage) and I have a U0100 code. I have checked all the connectors (even took them off and cleaned them with brake cleaner), batteries are in good order, and I am at a loss. Any suggestions will be welcome.
     
  2. rjparker

    rjparker Tu Humilde Sirviente

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    No ready? Checked the ecm connector? Two step on hv disconnect after pushing it in?
     
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  3. jim11132

    jim11132 New Member

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    Hello I picked up a 2012 Prius v wagon for a swan's song because it had a blown headgasket. I bought it to give to my granddaughter but now beginning to doubt my own wisdom. I have never worked on a hybrid before so the stuff beyond the IC engine is new to me. Had the head resurfaced, valves ground and new headgasket, chain, etc. In so doing I pulled the wiring harness off to the right side of the engine (viewed from front) and tied it out of the way with a strap. After reconnecting everything (at least that is what I thought) I was anxious to drive it out of my shop. However, not! Engine would not even turn over. I got U0100 code and message (My reader does not provide the secondary bits, 211, 212, or 530). I have gone over every connector, cleaned them with brake cleaner, etc. to no affect. I even popped the two large connectors off the ECM and cleaned them. No corrosion - clean as a whistle. Batteries are charged. I have ordered a cable so I can put Techstream on my notebook so I don't at this time know which of those 3 secondary codes might come up. However, in the meantime can you all give me some advice on where or how to chase down each of those codes?

    I assume the ECM in this DTC code message is the "computer" on the right fender well with the two connectors I described above. However, where is the PCM? Please don't tell me it is behind the glove box. And, how does this CAN work. Are there copper wires, fibre glass, or what between the various ECM units?

    Additionally, I saw a website that described how to reset the ECU. He said to disconnect the HV and LV batteries, unplug the heavy power cord in the fuse box, wait a few minutes, reconnect the HV and LV batteries, replug the power in the fuse box, press the start button on and off 3 times. Does this really work or does the car simply burst into flames? OK, its been a long day. Thanks for your reply. Jim
     
  4. Brian1954

    Brian1954 Active Member

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    Continues this discussion in your original thread: https://priuschat.com/index.php?posts/3459194
    Put all or additional information in that thread.

    This thread is for Gen 2 Prius. You have a Gen 3 Prius v, which is completely.

    Note that your first 5 posts are looked at by the forum's moderator, and it could be delayed by 12 hours until it appears on the forum. After your 5th post, they will appear on the forum right away.
     
  5. ChapmanF

    ChapmanF Senior Member

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    Totally.
     
  6. Tideland Prius

    Tideland Prius Moderator of the North
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    Moved posts to this thread
     
  7. jim11132

    jim11132 New Member

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  8. jim11132

    jim11132 New Member

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    Hello - continuation to my prior message--
    I made several measurements at the ODB connector. Here is what I found (R means resistance in ohms and V means volts DC):
    Bat neg disconnected
    R(chassis gnd, signal gnd) = 0
    R(CAN gnd) = open - infinite resistance
    R(CAN lo, gnd) = open
    R(CAN lo, CAN hi) = 61
    R(CAN bat) = open
    R(CAN lo, bat) = open

    Bat neg connected
    V(bat, gnd) = 12.31 - special case, power down console. Following cases with console powered up
    V(bat, gnd) = 11.86
    V(CAN gnd) = 2.46
    V(CAN lo, gnd) = 2.17 their sum is 4.63 rather than 5v as expected

    It appears that the CAN is powered via a relay since the resistance measurements show it to be totally disconnected from the battery when the battery is disconnected. However, it must be connected when the power is applied since there is measurable voltage, albeit slightly low.

    I downloaded a copy of Techstream and tried to apply it. It could not communicate with the network so it is somewhat useless at present. When I ordered it to test the network it went into a never ending attempt to find the network. However it seems the network is active based on the two voltage measurements, it is not grounded, and there are no breaks in the lines since the terminating resistors were both found (61 ohms).

    One final bit: When we got the engine back together, my grandson started it. It ran for about 5 seconds until I screamed at him to kill the engine because it made a loud rattle. I thought I failed to get one of the valve stem caps on or a rocker fell off. I folded the wires back again so I could pull the cam cover. Nothing out of the ordinary was found so I have concluded that the oil drained out of the tappets and had not refilled before we killed the engine. After putting the cam cover back and reattaching the various sensors, etc. we have had this dead system problem.

    Hope someone can provide some suggestions or even an answer. Thanks
     
  9. vvillovv

    vvillovv Senior Member

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    Not knowing what U0100 is I looked at what came up in search. And this is what I found '
    Error codes U0100 and U0101 | Toyota Nation Forum

    to save you some time - scroll to post #11 by Protech than read # 13 and 14.

    the reason I believe it might help you is that my first thought while reading your posts was
    "where did you download techstream from and what are you using between the car and techstream ? if you're using techstream connected to the car and not just the docs.

    The main jist of what I'm seeing for U0100 is that it's typically set by other codes and rarely if ever is set as the only code.

    If you're using techstream connected to the car, again, what are you using as a passthrough connector between techstream and the car? , be as specific as possible, also repeat what's happening with the connection and what if anything is showing up in techstream.

    If you're seeing anything in techstream - be looking for other codes beside U0100 especially for other codes and their ( 3 or 4 digit INF codes ) techstream detects.



    edit: in the OP (Original Post #1 above ) you mention the starter not engaging. Most hybrids don't initially engage a typical starter. And many don't always start the engine when put into READY mode, since the high voltage battery provides the means for starting the engine.

    ECU controls when the engine runs and when it doesn't run (by talking to the ECM, I believe).
    Yes, but double check in techstream docs: ECU electronic control unit ECM engine control module

    see also: maintenance mode in the techstream docs.
     
    #9 vvillovv, Jul 12, 2024
    Last edited: Jul 12, 2024