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2019 4HI & 4Lo Lights Flashing!

Discussion in 'General Tundra Discussion' started by Ronin73, Jul 16, 2019.

  1. Jul 16, 2019 at 5:58 AM
    #1
    Ronin73

    Ronin73 [OP] New Member

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    Hello!

    My 2019 started having this issue on the way to work this morning. The 4hi and 4lo lights in the dash started to flash simultaneously and won't stop. The truck is not in 4x4 and I have stopped the vehicle, turned it off, and then started it, but the lights still flash. Any ideas?

    I am dropping it off at the dealer this evening. Just thought I'd ask to see if anyone has experienced this before. Thanks.
     
  2. Jul 16, 2019 at 7:25 AM
    #2
    Ronin73

    Ronin73 [OP] New Member

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    Update*

    It has been sitting for a couple of hours here at work, so I went and started it and the flashing has stopped. Still concerned, though, so I am going to drop it off at the dealer, but with it no longer flashing, they are probably going to say they can't do anything.
     
  3. Jul 16, 2019 at 7:34 AM
    #3
    bfd300

    bfd300 New Member

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    See if you have reverse lights
     
    Ronin73[OP] likes this.
  4. Jul 16, 2019 at 7:40 AM
    #4
    cmiller219

    cmiller219 New Member

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    I was having similar issues with my new 18 within 500 miles. On off on off so i took it in and they were off but I described what was happening and it needed a tune or software update. Maybe that’s all it is. I know not much help
     
  5. Jul 16, 2019 at 7:43 AM
    #5
    Lake.Life24

    Lake.Life24 New Member

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    This happened to my 2018. Not sure what the issue was but I had to put the car in neutral shift to 4Lo and drive forward and reverse a few times. Then I shifted to 4Hi drove for 2 minutes until the light stayed constant. Then I turned it to 2Wd and havent had a problem since. It seemed like the car was just confused and took a bit for the computer to figure out what it wanted
     
    bulldog93 and Ronin73[OP] like this.
  6. Aug 8, 2019 at 7:35 PM
    #6
    Kerch71

    Kerch71 Surgical Precision

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    It's most likely your brake stroke sensor. Mine does a similar thing when I start the vehicle. If I put it in neutral, then engage and disengage 4 Hi, then put it back in park, it usually stops. A friend of mine is a GM Certified mechanic, and he's replaced a number of these on Tundras that were all doing a similar thing. For some reason, Toyota wants the computer to measure your brake stroke. I promise I'm not making this up. Not sure what the stroke has to do with 4 Hi and Low, but there you have it. Hope this helps.
     
  7. Aug 9, 2019 at 4:37 AM
    #7
    Ronin73

    Ronin73 [OP] New Member

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    So, nothing to worry about? Hasn't done it since and everything is working properly.
     
  8. Aug 9, 2019 at 4:42 AM
    #8
    Midnite72

    Midnite72 Anything DIRT !!

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    Sounds Like stupid computer BULLSHIT !!

    Got to love technology

    Hope u get it straightened out bud
     
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  9. Aug 9, 2019 at 7:42 AM
    #9
    Kerch71

    Kerch71 Surgical Precision

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    I wouldn't worry too much about it. I keep meaning to get the sensor changed just because it's annoying. Mine seems to go through spurts where it will do it everytime I start the truck, then it will stop for a few months. Been meaning to replace the sensor for at least a year. Just lazy but also not that concerned.
     
    Ronin73[QUOTED][OP] likes this.
  10. Dec 7, 2019 at 6:36 AM
    #10
    Ronin73

    Ronin73 [OP] New Member

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    Well, after this stopped last time when the vehicle was restarted, I haven't had any issues. It began flashing again on my drive into town yesterday and I immediately took it to the dealer. The ran diagnostics and the following code came back: P17A8. They said this indicated an open circuit in the transfer shift motor drive. They checked it out and said they couldn't find anything loose at all. They cleared the codes and said to come back if it happen again.
     
    Last edited: Mar 13, 2020
    bulldog93 and GODZILLA like this.
  11. Dec 7, 2019 at 6:47 AM
    #11
    Sas

    Sas Humor is everywhere

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    Lost track after #1.
    Could be a bad ground connection on the harness itself. This is for a Taco, but likely similar diagnostics and solutions:
    http://www.ttguide.net/transfer_shift_motor_control_circuit_circuit_open_p17a8_-1481.html
     
  12. Mar 13, 2020 at 12:49 AM
    #12
    mrflyinghigh

    mrflyinghigh New Member

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    I have the same thing. Took it to the dealer, no code cause it stopped flashing, and everything was working as advertised. Happened again a week later, they ended up changing the 4wd actuator. A month later, it’s still happening occasionally. Planning on taking it in soon, but i can’t plan on the lights flashing. It resets once the truck sits off for a while, and who knows when it comes back. Could be the next day, could be months....very frustrating
     
  13. Jan 20, 2021 at 8:09 AM
    #13
    Beef

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    Did any of you folks ever get this figured out? I am having the same issue with my 2020. 4Hi 4Lo lights blinking and a AWD malfunctions notice coming up on my screen on really cold mornings. The blinking and message leaves after 5-6 miles of driving and doesn't come on the rest of the day. Annoying as heck. Took it to the dealer and by the time i get there the codes are off. Left it overnight (of course its only in the 40s). No codes thrown and no history of any faults come up..
     
  14. Jan 20, 2021 at 8:17 AM
    #14
    Yoder18

    Yoder18 Veteran underwater basket weaver

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    Mine is an 18 and has done this since I drove it off the lot but only really happens during the summer/fall time. If I take it to the car wash it trips something and sends the 4hi/lo lights after which I can’t engage 4wd and just have to let it sit or drive w it on for a while. It’s annoying as hell but the dealership didn’t know what to do about it either.
     
  15. Jan 20, 2021 at 9:08 AM
    #15
    Beef

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    Thanks for the reply but that is some bullcrap from Toyota right there. Mine has been only when it drops below 35.
     
  16. Jan 20, 2021 at 12:05 PM
    #16
    Ronin73

    Ronin73 [OP] New Member

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    After my visit to the dealer, it has never happened again.
     
  17. Jan 20, 2021 at 12:14 PM
    #17
    Beef

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    Well they are clearing codes for mine now so hopefully it does the same. Thanks for the reply
     
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  18. Jan 28, 2021 at 12:39 PM
    #18
    JFever

    JFever New Member

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    I AM WAY BEYOND FRUSTRATED WITH THIS PROBLEM ON MY TUNDRA! I have 4hi 4low flashing plus every other warning light illuminated. 4WD will not engage. Just got 20" of snow this week. Need to be able to get my girlfriend to her cancer treatments. More snow coming tonight. Bought a quality code diagnostic tool and reset everything. Then it immediately lights up with warnings again. Took it to the dealer and they don't know anything. Said its because of me altering the truck with a lift kit and larger tires. Tried the zero calibration reset and followed all instructions per posts showing the paperclip method. Super stressed.
     
  19. Jan 28, 2021 at 1:34 PM
    #19
    timsp8

    timsp8 Former Tundra owner for 13 years

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    This might help. Or not. Just 4 hi and 4 lo flashing means 4wd switch between positions or unknown cause.

    Not my chart.

    457C4FAA-0BB4-4538-B2E9-A8EE4A89CDC2.jpg
     
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  20. Jan 28, 2021 at 3:57 PM
    #20
    Beef

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    Unknown cause?.....that's some world class BS right there..

    They told me I had a loose connection an actuator. They tightened but it still lights up. Its gone much quicker now but it still does it. Gonna take it back into them when it real cold and let them keep it over night.
     
  21. Jan 30, 2021 at 9:56 AM
    #21
    Yoder18

    Yoder18 Veteran underwater basket weaver

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    Strange mine will only do it when it’s hot out wtf
     
  22. Mar 28, 2021 at 5:39 PM
    #22
    LA184

    LA184 Living the Dream

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    I now have this issue, too. It's only happened when my 4Hi is engaged, and it clears up within an hour. I was having some issues engaging 4wd beforehand, but now it works. However, the flashing 4hi/4lo began today when out on the dirt, randomly.
     
  23. Jul 23, 2021 at 4:19 AM
    #23
    Flash_Outdoors

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    Has anyone found a fix for this? Lights flashed on me a month ago on the way yo work. Stopped and haven’t done it since. Jumped in the truck this morning, threw the truck in reverse, and boom, both lights flashing. They stopped by the time I got out of the neighborhood. Drove 1 mile and they started flashing again. Pulled into the gas station, put it in park and the lights went off. Sitting here idling now, no lights. Truck has 109,700 miles so I’m assuming Toyota will tell me to get bent.
     
  24. Jul 24, 2021 at 1:33 PM
    #24
    Beef

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    After many tries of fixing connections and rerouting wires, the dealership replaced the whole actuator and I've been 4 months blinking light free
     
  25. Aug 7, 2021 at 6:01 PM
    #25
    Beef

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    the post above you did…
     
  26. Sep 13, 2022 at 11:24 AM
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    2015sr5tundra

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    Soooooo, I just ran into this thread searching for the same solution to the blinking 4hi and 4lo , did anyone ever change the brake stroke sensor ? Or is it just a myth on weather it fixes the issue or not. My 2015 crewmax sr5 does the same thing and it seems as if it only does it in hot days , not sure what to do and wouldn't want to replace the actuator if it isn't broken.
     
  27. Sep 13, 2022 at 11:26 AM
    #27
    Yoder18

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    My 2018 still does it on hot/muggy days upon startup as well as when I go through the car wash. Annoying as hell. They replaced some sensor, I’ll look when I get in the truck and let you know but it still does it regardless. They scratch their heads and just stare at me. Still trying to find a fix for mine too
     
  28. Sep 13, 2022 at 12:44 PM
    #28
    Cruzer

    Cruzer Wheeling Full Size

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    I had this problem when I went wheeling. It turned out to be a loose connector/connection on the front diff ADD unit. Used a zip tie to keep it clamped down.
     
  29. Sep 14, 2022 at 7:30 AM
    #29
    excelw

    excelw AfRo Samurai

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    maybe try checking the abs sensors:monocle:
     
  30. Nov 18, 2022 at 7:46 PM
    #30
    Superbsdad

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    I have ran into this same issue. It started after I had my pads and rotors replaced. Is there a sensor that may have been damaged during the brake job?
     

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