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Yellow Box Speedo Calibrator

Discussion in '1st Gen Tundras (2000-2006)' started by Darkness, Sep 22, 2018.

  1. Sep 22, 2018 at 7:39 PM
    #1
    Darkness

    Darkness [OP] New Member

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    I recently stumbled across something in a land cruiser forum that got me excited. YellR, a company which makes the Yellow Box speedometer calibration device, had built a plug and play version to work on the Aisin transmission.

    To my knowledge this has never been available for our trucks, everyone who I have seen install a calibration device had to either solder into the wires at the sensor or solder in the wires behind the speedo.

    I took a good look at the plugs on that land cruiser model and figured they were the same as the speed sensor on my transmission. I reached out to YellR by email to ask if it would work, they were confident that it would. Ordered one up with 2 meters of harness and crossed my fingers. $110.85 and around 2 weeks later it arrived.

    First thing I did was carefully remove the wire leads from the plastic plug which connects to the Yellow Box. There is a special tool for this but I went in with a good safety pin. I then went under my truck with a mouth full of zip ties and a clipper.

    Disconnected the plug on the vehicle speed sensor, observed how it was binding on another wire loom and tucked it to the other side of that loom. Then I plugged in the Yellow Box harness, it just goes between the factory harness and the speed sensor. It's fairly idiot proof and took a bit of pressing to click in place. Gave the plugs a tug to be sure, then started looking for a route. I used some 3/8" plastic tubing to shield the harness, I may at some point insulate it with heat proofing since it passes near the header flange, but I was able to route it a reasonable distance from the hot stuff. I tied the harness to another harness every foot with a zip tie and went up the firewall and under the master cylinder, then pushed the wire leads through the grommet next to the fender.

    The wire leads popped through near my parking brake pedal, I inserted them back into the plastic plug and made sure they were seated well. Plugged that into the Yellow Box and turned on my truck.

    I saw the red and green lights flash, then the red one began flashing codes at me. It uses a series of quick and long flashes to let you know what it is set to. When you drive it flashes green then stays green until you slow down. I did the math and knew my speedo was around 9.6% faster than actual speed, verified by GPS. To calibrate, I parked the truck with the motor running and held both buttons down until they flashed a few times. Then held the red + button until it flashed about 10 times, then went for a drive.

    I verified that I was getting closer to correct by driving with a GPS speedo on my phone, went to park after a bit and made further adjustments. After about 3 rounds of this my speedo is now dead on, I double checked by driving through a speed checking sign at 45 mph, perfect. I tucked the box behind the kick panel so I won't get distracted by the flashing lights.

    If you want your speedo corrected I strongly recommend getting this. It's significantly cheaper than the only other option I have seen and the install is way easier.

    I might have been better to ask for 2.25 meter length harness, that would have been perfect but I got what I needed out of 2 meters. Took me about 30 minutes to run the harness and plug it in, another 30 to get the calibration right.

    Order here, make a note in the comments that you need 2.25 meters of harness. Great company and great customer service, Jennifer was very helpful for me.
    https://www.yellr.com/

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    Last edited: Sep 22, 2018
    bmcdds, seth419, TX-TRD1stGEN and 8 others like this.
  2. Sep 22, 2018 at 7:48 PM
    #2
    bmf4069

    bmf4069 New Member

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    Wow. Good info. You sir, are a gentleman and a scholar.
     
    Darkness [OP] likes this.
  3. Sep 23, 2018 at 6:23 PM
    #3
    Outbound

    Outbound American stuck in a Canadian body

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    Fantastic. Added to the must have list.
     
  4. Nov 5, 2018 at 8:20 PM
    #4
    Darkness

    Darkness [OP] New Member

    Joined:
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    Male
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    The darkest
    It's really dark
    Disclaimer! I have heard that these may not work on 05-06. Check with Yellrbox if you have that model.
     

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