Prius wont get into ready mode, immobilizer (car+lock) symbol lights up

Discussion in 'Prius v Care, Maintenance and Troubleshooting' started by waldox, Apr 22, 2022.

  1. waldox

    waldox Junior Member

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    Hi i need help, i have a 2012 prius v with 250k miles
    i reconditioned the hybrid battery 6 months ago
    pressing the brake and power button, i get the immobilizer lock+car light show up on the dash, and the intermittent brake accumulator go off.
    the remote fob locks/unlocks doors and interior lights work
    i charged the 12v battery
    changed the fob battery with a new one
    still no ready and same dash light.

    i popped the hood, found out i left the oil cap open it was just sitting on top and about 1/2 quart 500ml of oil splattered out
    i see lots of oil slick all over the top of the engine
    there is some oil around a couple of the spark plug connector clips
    oil around the front ground post
    oil around the front connector clips
    could it be the oil making a bad connection somewhere near the engine?
    or fuse, hybrid battery gone, hybrid battery safety plug unseated, try my other fob with new battery, oily ground post on the front of the engine, animals eating the wiring in the car.

    any ideas why i cant get into ready mode?
     
    #1 waldox, Apr 22, 2022
    Last edited: Apr 22, 2022
  2. waldox

    waldox Junior Member

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    i sprayed down and disconnected the oily spark plug connectors on the engine with dish soap and rinsed with water and let it dry will report back it if fixes it
     
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  3. bisco

    bisco cookie crumbler

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    and check the 12v health at the jump point under the hood with the car off.

    also, make sure the brake lights come on when you step on the pedal.
     
  4. waldox

    waldox Junior Member

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    update1: checked the engine bay fuses, they are good
    check the 12v point under the hood reading 12.5v
    tested both fobs with fresh battery, no go
    my mechanic suggested to disconnect 12v battery and hybrid battery fuses then spray brake cleaner around the engine to clear up any oil residue in the wiring.
    the 12v is not booting the car computer
    im thinking most likely its animals getting into the ecu wiring or the oil spraying everywhere affecting a connection
     
    #4 waldox, Apr 22, 2022
    Last edited: Apr 22, 2022
  5. bisco

    bisco cookie crumbler

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    could be. check the air and cabin filters for signs of rodents
     
  6. waldox

    waldox Junior Member

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    update2:
    checked 125a fuse under the hood and electrical box with multimeter it is ok, also confirmed by brake lights working.
    checked the fuses they seem to be working, testing by using the contacts on the top with a multimeter (corrrect?)
    checked the 5 30a fuses in the driver side (they do not have contacts on the top),4 manually pulled out and tested ok, 5th i checked visually is ok

    bisco thanks for the suggestion, i will put out the cabin filter and see if there is any evidence of rodents. i know there is an entry way from the cabin filter and the car ecus are near there infront of the passenger side.

    one thing im curious about car fuses, when i checked some of the 10a red fuses in the driver side cabin. if i have one negative lead on the left top contact of a fuse and then the other positive lead on the right contacts of the next few 10A fuses they all were connected (short). is that a short somewhere or normal behaviour? this is with car off, battery disconnected.
     
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  7. ChapmanF

    ChapmanF Senior Member

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    That's pretty much to be expected. As you can see when you look through the wiring diagrams (more info), it is very common for several fuses to be connected to a common power feed on one side. The separate branch circuits that originate with those fuses are ultimately getting their power from the same upstream place. In fact, more than just "very common", this is pretty much the textbook way fuse boxes are built.

    So all the test terminals on the supply sides of those fuses will measure as connected. And because intact fuses have continuity across, the test terminals on their load sides will look that way too.

    [​IMG]
     
  8. waldox

    waldox Junior Member

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    update3
    cabin filter was fine, just crimped in half, no sign of animal activity.
    opening the lower passenger glove i see there are a few ecus hidden there

    chapmanF: yes i figured it was normally connected on one side

    next steps are to get the wiring diagram and trace the power button and check that it the wiring works, hopefully its the power button!
    next trace the main ecus, immobilizer and the systems that power up the engine and hybrid system
     
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  9. waldox

    waldox Junior Member

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    update4
    amazingly i got techstream to connect to the car even with the car shut off and on 12v battery
    pulled the historical & current codes U1133 Lost Communication with PMN Module
    and historical code b278c Lost Communication With Power Source Control

    techstream pulls limited codes but still works!

    anyone with the repair manual for these two codes? much appreciated!
     
  10. waldox

    waldox Junior Member

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    206613_upload_2021-5-31_14-55-27.png 206614_upload_2021-5-31_14-56-52.png 206615_upload_2021-5-31_14-58-30.png 206616_upload_2021-5-31_15-18-34.png 206617_upload_2021-5-31_15-18-55.png 206618_upload_2021-5-31_15-19-51.png i found these might be related pics
     
  11. waldox

    waldox Junior Member

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    followed the diagnostic path for b278c
    i checked the voltage from the power management ecu coming from am2 fuse #1 & #7
    it was showing 4volts and was expecting 12v
    i have a few questions

    what could be causing the low voltage? bad corroded wiring? faulty relay? any other reasons for the low voltage?
    also is the "?" part circled the relay or a junction?

    could a solution be to bypass am2 fuse and run a new line from fuse box to power the ecu with a new fuse? or find the bad wiring/relay?

    lowvoltage am2.jpg
     
  12. ChapmanF

    ChapmanF Senior Member

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    The thing with the 3A and 3B designations is Junction Block No. 3.

    Though it's in the "relay locations" section of the wiring diagram, there aren't any relays in it. It's just a whole bunch of pins with a certain "inner circuit" joining them together in groups, as a convenient alternative to building a wire harness with a bunch of individual splices.

    jbno3.png

    ipjb.png
     
  13. waldox

    waldox Junior Member

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    sweet i had a feeling its a junction. im going to hardwire from fuse box to the two low voltage pins at the power mgmt ecu.

    do i need to fully disconnect the two white wires from am2 fuse box to the power mgmt ecu before adding a bypass wire from fusebox to the two white wire ports (low voltage), or keep the existing wiring as is?
     
  14. waldox

    waldox Junior Member

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    Final update
    i was able to fix the problem
    followed the diagnoses for b278c
    checked the two power lines from am2 going to power mgmt ecu, both should be showing 12v but only showed 0.6v
    wired up some wiring from fuse box to the two low points and everything works now! no more codes!
    thanks to travis from reddit for providing the diagnoses documentation
     
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  15. Arob21

    Arob21 New Member

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    What repair manual are you using waldox? I have a very similar issue with my prius that I can't figure out
     
  16. waldox

    waldox Junior Member

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    someone with techstream access sent me the repair diagnostics for b278c pm your email and i send it to you
    that faulty 12v wiring caused the u1133 code showing up

    you should get the codes with techstream, it can read limited error codes without being in ready nor acc mode
    there are hundreds of wires to check behind the glovebox connecting the 3-5 ecus, so it will be hard to diagnose without the code.
     
    #16 waldox, May 4, 2022
    Last edited: May 5, 2022
  17. Arob21

    Arob21 New Member

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    [email protected]
     
  18. ChapmanF

    ChapmanF Senior Member

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    That's a question that comes up from time to time. Sometimes, if you wait long enough, another member comes along and reposts small bits of the manual that you need. But if that doesn't happen right away, or you just want the information without waiting, it's also good to know where you can get all of it yourself whenever you need it. :)

    Toyota Service Information and Where To Find It | PriusChat
     
    #18 ChapmanF, May 5, 2022
    Last edited: May 5, 2022
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