Yellow Box speedometer recalibrator (1 Viewer)

[AmericanKing]

Searching for a speedo correction for my 04 Sequoia and came across the Yellow Box speedo recalibrator on Tundra.com. The earlier models tundra used a plug and play harness. The 05 and up A750 used a spliced harness into the the ABS ecu. This mod is popular in the 80 series forums. I just cant find anything for the 120 series. Since our 120 share the same A750 transmission I'm assuming this is doable with a little help.

 

[Rednexus]

I ended up using SpeedoHealer V4 in mine, following the instructions on this thread. It requires you to remove the instrument cluster and splice into to the speed signal wire, plus splice into a power source and a ground. You can then mount the box somewhere hidden but where you can easily get to it to change the correction factors. So it's not plug-and-play, but is also pretty easy to install. The actual box is tiny (about the size of a box of Tic Tacs).

Know that's not the answer to your question....but wasn't able to find a plug-and-play version for the GX. I considered the YellowBox but didn't want to be a guinea pig for it. The SpeedoHealer seemed to be the easiest and cheapest option to splice in, with good success reported on this forum. It has worked perfectly on my rig and also corrects the odometer and MPG readings.

 

[AmericanKing]

I didn't know this was available till recent. Thanks @Rednexus for the lead on that write up. The speedHealer is similar to the yellow box. Their splice hardness also install on the back of the cluster or ABS ecu. I like this route better just because its been proven. Did you notice any different tranny shifts compared to not having the calibration. On the Tundra forum most are saying it helped with shift hunting and most of them are on 33's or 35's. I've notice shift hunting during the hot summer months.

 

[Rednexus]

No changes in shifting. It's behind the trans and ECM electrically so it probably won't affect them.