Speedo doesn't work after wheel swap
 

So two days ago I swapped my wheels from the factory Sport rays to my "summer" set. They are a little big so rolling diameters will probably be off... My issue is that since I swapped them my speedo doesn't work, abs is off, trac is off, and mykey light is on. Car also doesn't like shutting off ( have to hold the button).

In the previous years I've ran these wheels I haven't had an issue, apart from when I had it on the dyno. Same symptoms and cleared up in a few km.... But this time I've done probably close to 300 miles ish now total and it hasn't fixed itself. I did leave the battery unhooked overnight to see if that would help clear anything, it didn't.

Another thing I noticed is when I give it some gas and the rear slips a bit in second or third is that it seems to correct itself, all warning lights go away, speedo works, but that only lasts for a minute or so after.

Does anyone have any ideas or tips and tricks? I plugged my computer into it and of course it comes up with the speed sensor code. But its fine with the stock wheels on.

Can you provide specs of your "summer" wheels?

275/35/20 front 315/35/20 rears on Pilot Super Sports.

So for comparison. The stock rear compared to the stock front is 0.4 inch less and 5 revolutions per mile more. While my summer set is 3.5" bigger around and 28 rev per mile less comparing back to front

By my calculations, your fronts are 673mm in diameter and rears are 697mm in diameter and the difference is ~24mm or an inch, which is going to be too much of a difference for the electronics. OEM diameter differences are ~5mm.

Are you sure these have been run on your car before ??

The difference in diameter of the back tires and the front tires has to be below a certain number (I cannot remember what that is, 3mm I think). Anything greater then that number messes up the computer.

But I've driven it for the past three years without issue with the bigger tire setup. It's only after I put them on for this summer did I have an issue

http://www.websleuths.com/forums/ima...lies/dunno.gif

Not the first weird thing to happen in Saskatchewan.

Start with checking the wheel speed sensors. Make sure they're still there and not damaged.

Put your other set of wheels and tires on and see if you still have the problem. If you still have the problem. Then you know it's not the wheel and tire combo.

So I swapped back to the stock wheels, all the gauges and warning lights fixed themselves after driving for like fifty feet... I put the "bigger" wheels on and within a mile, I lose my speedo, trac, abs, rev match, and the car doesn't think the key is in it so it's hard to turn off...... but if I go around a tight corner and give it a bit of gas, it seems to fix itself, but then after a mile I lose everything.

Very confused as to why these wheels worked for two years and now they don't. I really don't want to have to spend $1300 on new rear rubber when the ones on there have been barely used.

My guess is that one or more of the speed sensors is aligned so it just barely works with the stock wheels. Something about the new wheels disturbs the magnetic field enough to mess up the sensor signal. It may help to move the sensor(s) a little closer to the target.

If they worked before then maybe a little more air presure in the front tires and a little less in the rear may get it to work. You really need to get tires that are closer in diameter though.

Edit: What tire presures are you running now?

Even besides the speedo issue, those tires are significantly taller than stock

Better sizes would be 275/30/20 and 315/25/20

I leave everything stock size and have never had any of these problems, just my.02 cents..:driving:

I would have liked stock sizing. At the time I bought them, few years back... I was assured by the tire person that all will be good... and for two years all was good... and forking over a big chunk of change for new rears when these are practically still brand new is a hard pill to swallow.

So what I'm curious is there anyway to reprogram the computer or sensors or anything to accommodate the bigger tire?

That "tire person" should be fired. Probably wanted to make the sale on something in stock on the spot instead of doing more work

Its not just the tire height, its the difference in tire height

get tires that fit

These ones fit perfectly. I'm trying to find a simple option that will allow me to use the still next to new $1300 rear tires that I already have. So if the only advice you can say is get new tires, I'll gladly take your donations.

You are assuming there is a simple solution


Sell your tires to a GTR owner

Looking at your tire size specs.

275/35-20. 27.6" diameter.
315/35-20. 28.7" diameter.

You're over an inch difference in height. .7" is about the limit the you can run without the lights coming on. Don't know why you didn't have problems before.

Jesus that rear is ridiculous. Monster truck status.

Has your car received a software update at the stealership since the last summer ??

Either that or marginal wheelspeed sensors is the only source of problems

Car hasn't been back to the stealership since I bought it in 2012. If there is any update, might it affect my tune?

If you have a tune and take the car back to the dealer. They do a flash up date. Your tune is gone. You have to remove the tune to save it before you take the car in. Or TELL them DO NOT FLASH THE COMPUTER! Alot of times, they don't listen to you anyway and flash it.

So for an update. After about three days of driving with no speedo and other goodies that come with. Engine threw the P0500 vehicle speed sensor malfunction... think something could actually been wrong with the sensor or is this just a by product of the bigger wheels?

If you didn't do what SouthArk suggested, do that. Otherwise, find out what wheel speed sensor went bad and replace it. I suspect what you will find is something knocked the wheel sensor out of alignment. :ugh2:


Not to be a difficult person, but did you even look at the sensors? Hory chit batman, if all that stuff wasn't working on my car, I'd have it up in the air, checking for issues, not continuing to drive it with a non-functioning ABS and speedo.... can you say 'LAWSUIT' if you had been in an accident? Great googly moogly dude, fix your chit... don't post on the inter webs that you are continuing to drive with stuff not working right... :shakes head:

That's not even close to fitting 'perfectly'. Unless there is a difference between Saskatchewan perfect and everywhere else.

Whether you want to hear it or not the answer is get tires that fit.

For reference, your front tire does in fact fit pretty much perfectly. Your rear tire is over 2" taller. That is a massive difference. Get new rears and put the current ones in a tractor or something. That's about all they are good for.

His insurance company won't pay a dime if they find this thread :eekdance: