Hypertech’s Speedometer Calibration Module

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The Tundra’s ECU, or engine control module, administrates most aspects of your truck. Transmission shift points, air/fuel mixture, engine timing, and other performance settings are controlled by the ECU, as well as more mundane settings like overall tire size. In the world of after market parts, selling programmers that can change these ECU settings has become a big business. Factory engine calibrations usually emphasize things like emissions and fuel economy – change these factory settings (even slighty) and you can often add significant power.

Unfortunately for us, Toyota isn’t a fan of after market engine programmers. Toyota designed their ECU in a way that makes changing factory computer calibrations nearly impossible, even when it comes to changing the most basic of settings. Fortunately, when it comes to oversized wheel/tire packages or gear changes, Hypertech has come up with an in-line Speedometer Calibrator Module that allows you to compensate for your wheels and tires without having to re-program the ECU.

Hypertech Speedometer Hypertech inline calibrator

NOTE: To date, Hypertech is one of the only aftermarket tuner/programmer companies with Toyota Tundra applications. And, although the speedometer calibrator does just one of the many jobs we expect from this upgrade, the engineers at Hypertech are working on creating a programmer for the Tundra.

By now, we all know how this stuff works. Stock ECUs are programmed for stock equipment – that includes a specific tire diameter and stock gears. Your speedometer, odometer and part-throttle shifting are all based on stock parameters. A larger diameter tire goes faster and farther than the ECU realizes, resulting in your speedometer showing your speed to be lower than it really is. While this probably seems like a minor inconvenience for the extra traction and clearance flotation tires provide 4x4s, it’s not really legal. Vehicular codes require a correctly calibrated speedometer and odometer. Not to mention that, in terms of performance, the transmission hasn’t been clued into the changes and your shift patterns won’t match your actual speed. Shift points are based on road speed, which the vehicle system determines by wheel speed. If your speedometer is off, your transmission is off too.

The Hypertech speedometer calibrator allows for an unlimited change in both tire diameter and gearing. You could turn your Tundra into a Monster Truck (and send us the photos if you do) and the calibrator will still provide accurate readings and shifts on all three Tundra engine options.

Installation definitely does not require a software degree, but it does require access to a PC. The Speedometer Calibrator Module kit includes a USB cable and software CD. You plug the module into your home computer and log in the new tire height and rear gear ratio. Next, you’ll need to get behind the dash, disconnect the factory connector to the instrument cluster, and snap in the Hypertech module (see instructions pdf). If you’re comfortable pulling your dash apart, this is a pretty simple job. Now, you’re ready to roll with accurate speedometer and odometer readings and corrected part-throttle shifting.

The cost on this part is about $220 – but you may have to call to get it, as they’re still not quite in stock at a lot of after market retailers.

Lifted Tundra with oversize wheels.

Think this truck has a speedometer calibration unit?

Filed Under: Toyota Tundra Accessories


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  1. […] Tundras ! Not sure if any of you are interested , but found this interesting . Hypertech’s Speedometer Calibration Module | tundraheadquarters.com What do you use to correct your calibration now ? __________________ 2008 Crewmax X-SP carbon […]

  2. […] Tundras ! Not sure if any of you are interested , but found this interesting . Hypertech’s Speedometer Calibration Module | tundraheadquarters.com What do you use to correct your calibration now ? Here’s the install instructions , it looks easy […]

  3. TXTee says:

    Jason – not sure if this is true or not, but the advertisements say you just plug into a connector but didn’t require digging behind the dash. Anything changed since the time of this article? I’m trying to have an easy flash process when I go about this.

  4. TXTee – Unless Toyota has moved the connector, you’ve still got to pull the dash apart a little to add this accessory (at least that’s what the instructions show).

  5. Marcus says:

    Would this be necessary with a 3/1 leveling kit with 34-35 inch tires. Looking at tires in that range and wondering how much of a change i will see if i don’t put this thing in. Is it bad for the engine if i don’t, and if i do how hard is the install, pulling the dash apart scares the hell out of me as I am not mechanically inclined.

  6. Jason says:

    Marcus – Not really necessary, but can’t hurt. The overall increase in tire circumference from a 32″ tire (stock) to a 35″ tire is about 9%…you truck’s speedo will read about 10% slower than you’re actually going. So, if you speedo says 55mph, you’re actually doing 60mph. If the speedo says 30 mph, you’re actually doing 33mph. This difference is small enough to be within the limits of accuracy of a typical speedo (which tend to read a little fast at lower speeds anyways). The issue is at highway speeds. If you’re going 80mph on your speedo, you might be going 90mph in real life…and that’s a hefty ticket. SO, if you don’t want to mess with a calibration module, just remember to take it a little easy on the freeway.

  7. Marcus says:

    Thanks, that is what i figured. Might have to bite the bullet and buy it and convince someone with some know how to help me put it in.

  8. Jason says:

    Marcus – LOL! I bet you can manage. The hardest part of working on the interior is pulling those clips. It’s something that’s nice to have some experience with, so if you can con someone who’s done it before into helping you it will help with piece of mind…but it’s definitely not too hard for anyone with a little technical knowledge.

  9. […] reads so your shifting is jacked up, you need to install the hypertech to correct that. http://www.tundraheadquarters.com/bl…ration-module/ __________________ 2010 CrewMax SR5 5.7 – 4X4 TRD 4" Lift (OME 612's + 1/2" CB […]

  10. […] quick google search and I believe I found the article. Would it be this one? Hypertech's Speedometer Calibration Module | Tundra Headquarters Blog That's a very informative article on the problem and how the ecu works… After reading this I do […]

  11. Ron says:

    Im installing a 2.5 leveling kit and going to a 20×9 rim with 305/55/20 tire 33’s. Will i need to get this upgrade, don’t want to mess with it if i do not need it. Thanks

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