Speedometer calibration

364 Views 5 Replies 4 Participants Last post by Mr Breeze, 10 d ago

Shadious

Discussion Starter · 21 d ago

We have a base model 2018 that came with 18” wheels all around. We upgraded to factory 18/20” wheels from an SLR. Our speedometer is off by about 5 mph at 75mph. The local dealer says they can’t “reflash” the ECU to let the vehicle know the wheel size changed. Has anyone had their dealership do the reflash? If so, can you provide me your dealers’ contact information? I want to get this done, as it is annoying to have inaccurate speedo readings since we do Turo rentals. *

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Shadious

Discussion Starter · #2 · 19 d ago

Just wanted to follow up to see if anyone had any suggestions to my question.

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hrca0434sc

· #3 · 17 d ago

Shadious said:
Just wanted to follow up to see if anyone had any suggestions to my question.

Since 2016 we advise the owners that changing wheel size will mess the spedo. The dealership can adjust only if you have oem and do not need reflashing but they need to get their computer to change sizes. I have 22 all around so there is no way to adjust. The other way around is that you get with someone that have a computer and the time to make an over lay that can be place over the spedo. You will need to open it and stick the new decal inside. You most run with someone inside the SS to check speed on SS and GOS to get the right number and let the guy know what changes need to be done.

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EjFord

· #4 · 17 d ago

When traveling I use a GPS for 'live location' (don't want some 'gal' telling me where to go) The GPS will give you your speed. The 'odometer' will still be off a little "Who Cares">>>>>>>>>>>>>> Ride and enjoy.

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Shadious

Discussion Starter · #5 · 16 d ago

hrca0434sc said:
Since 2016 we advise the owners that changing wheel size will mess the spedo. The dealership can adjust only if you have oem and do not need reflashing but they need to get their computer to change sizes. I have 22 all around so there is no way to adjust. The other way around is that you get with someone that have a computer and the time to make an over lay that can be place over the spedo. You will need to open it and stick the new decal inside. You most run with someone inside the SS to check speed on SS and GOS to get the right number and let the guy know what changes need to be done.

I have the larger factory wheels 18/20” so they are not that far off the original size. Since I rent this on Turo, I want the speedo to be correct- it would stink for someone to get a ticket due to incorrect speedo calibration. I think this is a case where the dealership is not aware they can reflash the computer with the larger wheel size.

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Mr Breeze

· #6 · 10 d ago (Edited)

I'm thinking the transmission is a aisin transmission if that's right there may be a drive gear on a speed sensor that can be changed you may need about to swap the sensor gear and get the miles closer I would definitely look into that. Finding someone that can write a program for the cluster may be hard to find. On the instrument cluster over lay these people may could make you what you need, they were great to work with on a motorcycle speedometer face plate that was pealing with age and sun for me. I emailed them told them what I was working on they said send a picture then made a face plate and made a link so I could order it. Found them on the web Venoxy gauge faces custom face plates. Pictures of my speedo before and with the replacement face taking the kilometers off really cleaned up the look when I did the repair. Check out the difference between the old and new face plate.

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