Can the speedometer be reprogrammed to correct MPH reading after changing tire size. There must be a constant in memory that the software uses to convert the pulses per second from the sensor to MPH on the dash. Can this constant be changed?

 

im my case... just drive past a police mph meter thingie on the side of the road that shows 'your speed' and compare with your speedo.

then just remember that xx mph is actually xx mph. unless you own like 4 cars it shouldn't matter.

 

Unfortunately there is no way to reprogram the Fit's computer at this time. I wish we had flashpro, but they don't like us for some reason.

The AEM fic can be connected to the speed sensor, and alter the signal, but its a pain.

Either remember the difference as kenchan said, or get an ultragauge.

 

Boy that is frustrating. I work with PLC and factory automation and just know it’s a matter of re-flashing a register in some eeprom or flashram. Can dealers do this?

 

They probbly won't. If you change tire size just find a size within 3 to 5% of the origenal and you should be good. Even tires that are the same "size" will actually have a different number of revolutions per mile if you look at the specs. Look up the miata.net tire size calculator, it will compair different sizes and give you the % difference. (Or is it .org? Google it :P)

 

how far off is your speedometer that this is actually a concern?

are you really that "honest" that you dont want to speed?
or are cops aroudn you that big of assholes that tehyll get you for a few MPG over the limit? if thats the case...you probly shoudlnt be pushhing the limit anyway.

 

To follow words already spoken.. http://www.miata.net/garage/tirecalc.html is a good website to get tire/rim in close to stock ratio so your speedo isn't too off. Hope this helps.

 

Another option is if you have a Scangauge you can set it's display to read out the actual mph. You can use a GPS too. Most show your mph.

 

All replies are practical workable solutions thanks. Real problem is me it just irks me knowing it can be made "right" with the know how.
Company I worked for made tiny gear box to allow the trans speedometer output be increased/decreased to adjust for tire/Axle combinations.
Mostly obsolete with pulse generators and programmable electronic speedometers

 

excellent post! duh, why did i not think of posting that! i see my actual speed on my GPS all the time. hahaha!!

 

I'm sure there is but I don't think Honda would allow that @ user level. Liabilities, liabilities... and lawyers lurking...

Options already mentioned: GPS, scan gauge/ultragauge all work as alternatives.

Here's a link to Discount Tire's calculator: Tire Dimensions Made Simple - Discount Tire

A good reference for/as a mental speedometer when changing tire sizes... Just my take...

 

yah considering the class action lawsuit against them for the mpg/odo errors recently, i seriously doubt honda will allow user to mess with it.

 

Don't know why but every time I read something about ESC/VSA or any variations of, it triggers "Ford Explorer." Just me...

 

hahaha

before technology there was the suzuki samurai tipping over claims.

 

that happened to me back when I was in my 20's my bud was exiting the freeway (cloverleaf) and next thing I know my face is about 10" from the ground!

 

It´s not possible, man.

 

I have a 2007 Fit Sport and used my Hondata. It was 15 mph more than gps speed. My tech reprogrammed my speedometer a lil which was still off by 10 mph but then I took the speedometer front plastic cover off, used my gps for accurate mph, pulled the mph needle out and drove off to 60 mph on gps and while steady driving, put needle back on speedometer at 60 mph. Now the speed is accurate!👌

 

Honda does not allow it on dealer level either. Honda dealer tools are very limited to reading and resetting error codes. Practically no modification or adjustment is possible. My local dealer is a multi brand dealer and using their words "Honda's tools are twenty years behind Mercedes', VW's or Opel's tools both in MMI and capabilities to do things".