Dealership won’t flash the speedometer to match tire size. What now?

[GRDIESEL]

My dealer did it last month. You can get the Tazer Lite if you are looking to take a little cost off it.

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[redrider]

When I purchased the Guzzi Cafe Sport, I also ordered the cables and software to access the bike's brain/FI via laptop. There have been several mods to the bike over time and the extra equipment has paid for itself many times over. If you have patience and some common sense, the savings add up. Back when the re-flash options were going live, some techs would hookup the car/bike and go make money(flat rate) on another vehicle at the same time. It is called double dipping. 125 USD for a flash? Nope.

 

[NachoRuby]

I don't mind paying the dealership to do it at all. But I'm concerned if they aren't allowed to do it. I'm just wondering mostly when the policy changed, why, and if it's nationwide or just certain states.

 

[AmishMike]

What was your stock tire size? If they were 31's then yes, 35's should make a difference.
My JTR had the stock 33's and I went to 35's. No calibration etc. every time I check my speed against a GPS, another stock vehicle or those "Your speed is" signs, it is right on the money. I have even heard people say that the stock Rubi was calibrated for 34's. I guess they expected everyone to go to 35's and those that stayed with 33's 'appeared' to get better mileage etc.. They split the difference so to say. Check yours to see if it is really necessary. The Tazer or similar product does have a lot of other neat options too.
In today's environmentally challenged world, I can see that they can no longer make that change at the dealership level. Theoretically it could change mpg etc..

 

[ShadowsPapa]

I see your point. But what bothers me is some dealers will do it for free, others want to charge or they give you the run around and say they can't.. I've had dealers lie to me in the past.

I had an Audi Q5 and a stone hit the A/C evaporator. The dealer I took it to wanted $600. They said warranty doesn't cover accidents, I tell them the grill is enormous and there's no protection. "Sir, our hands are tied by AUDI North America there's nothing we can do" I Went to a different dealer 20min away. They gave me an Audi loaner and fixed the problem free of charge--the service advisor told me the wide grill was a know design flaw.

My M3's steering wheel started to peel and the dealer wanted $500, they said it was a wear and tear item. I went to another dealer, explained to them how the peeling leather slips when wet and it's going to cause me to crash..The tech called someone from BMW corporate and Gave me a brand new steering wheel that day.

That's only two examples of at least 8 bad encounters with dealers...So I try to avoid them as much as I can.

I've had good luck with dealer shops but there's one I try to avoid. It's just a feeling, and their prices were a bit goofy.
I've seen other posts by others who appear to have been outright lied to by their dealership shops - things I know absolutely to be wrong either from my own experience as a mechanic, or, because my own local dealer told me the exact opposite and took care of things.

If this tire size mod thing is real - I'd love to know what's up with it. I may just go in and ask the local shop to see if they can find out and explain it to me. I don't need a change, I adjusted mine just a bit using jscan (l personally like it for tire size changes better than AlfaOBD because it's impossible to find the tire size thing in Alfa's 150,000 lines of things you can change while in jscan you simply type in "tire" and it takes you right there, you select a number and say GO.
Maybe I just don't know how to find it and use AlfaOBD - and if that's the case, I'll be the first to admit it. But with jscan it takes just seconds, easy.
I also like having things like AlfaOBD because, as in the case of my wife's Jeep - I could read the error codes and do a complex print out and hand it to the dealer.......... you should have seen their look when I handed them pages showing exactly where the misfire was, when, how often, etc.

Anyway - I'm really curious on this thing - why some say yes, others say they can't, some charge, some do it for free - it's baffling. I may take a TSB in and ask them - I don't need them to do anything but they seem to be ok with talking about things.

 

[ShadowsPapa]

What was your stock tire size? If they were 31's then yes, 35's should make a difference.
My JTR had the stock 33's and I went to 35's. No calibration etc. every time I check my speed against a GPS, another stock vehicle or those "Your speed is" signs, it is right on the money. I have even heard people say that the stock Rubi was calibrated for 34's. I guess they expected everyone to go to 35's and those that stayed with 33's 'appeared' to get better mileage etc.. They split the difference so to say. Check yours to see if it is really necessary. The Tazer or similar product does have a lot of other neat options too.
In today's environmentally challenged world, I can see that they can no longer make that change at the dealership level. Theoretically it could change mpg etc..

Mine was set to work perfectly with the Falken Rubicon tires. It was spot on - I don't use a speedometer as those don't show accurate enough and GSP is always a split second behind, depending on weather conditions and location. I use ODOMETER to calibrate. My Overland with the Rubicon Falken take-offs was accurate to the tenth of a mile over a 17 mile test trip.
With the new tires, which match the Overland Dueler stock tires in "diameter" I noticed that the speedometer (digital, not the analog dial as that's been wrong since day one) compared to GPS was about 1 mph off - likely closer to 1.5 off, because watching both the rate of change indicated it wasn't off by an even full point.
My GPS battery was dead (I use my old Garmin to calibrate, along with my phone) so I didn't get things completed, but the setting that was PERFECT for the falken - what everyone calls a 33 but is actually 32.7", was 32.75 in the truck (makes sense as some sites say the Falken is 32.7 and some say it's 32.8 so it's likely 32.75)
I set it back down to 32.25 which is what the stock Overland tire is and is what the General Grabber tires are. The GSP was matching the digital speedometer in my truck but I want to use my Garmin to check the ODOMETER against the truck. When I can drive 10.5 miles and the truck says I went 10.5 and my Garmin says I went 10.5, then I'll be happy.
If you are going 61.3 according to your truck it will say 61 but if it's really moving 59.6 the GSP will say 60 so you think it's just 1 off but it's really off by more. That's why I use miles driven, not just speed.

 

[cb4017]

Get JSCAN and an OBD bluetooth adapter and security bypass cable. There's a lot of posts about those here.

This is what I did OP. I had an OBD Bluetooth adapter laying around from when I used the Torque app. Ordered a bypass cable from Amazon for $25 and put the JSCAN app on my bat phone. When I hooked it all up I bought the JSCAN VIN license for around $20.

Worked great. Probably the most difficult part is getting the bypass cable hooked up. Got easier with practice.

 

[Gladman]

Goofy thing is according to the TSB it's supposed to be changed to comply with our federal regs! (keep odometers and speedometers accurate, etc.)

Well, then I guess it has to be an FCA thing in the US. And I have no idea why it would not be mandatory to change it in both countries. Perhaps there is a lawsuit fear about taking on a liability for a non factory change.

 

[Gladman]

When I calibrated my tires I used the stationary radar speed displays that show “Your Speed” common to slow down zones when approaching communities. Got it spot on at 50kph, 60kph, 70kph and 80kph. So while there may be an accuracy variance of +- 1 or 2 % from the radar readers, I think it is likely 1% or less.

 

[ShadowsPapa]

This is what I did OP. I had an OBD Bluetooth adapter laying around from when I used the Torque app. Ordered a bypass cable from Amazon for $25 and put the JSCAN app on my bat phone. When I hooked it all up I bought the JSCAN VIN license for around $20.

Worked great. Probably the most difficult part is getting the bypass cable hooked up. Got easier with practice.

I bought the extension, now I can have the cable and adapter connected in less than 15 seconds, and put back even faster.

I simply tuck the extension cables up on the trim under the steering wheel. When I need to connect the security bypass cable, I just reach up, pull the connectors down where I can SEE them, press the lock tab and pull........
The nice thing is, any direction - JSCAN, AlfaOBD, or any other solution that's been mentioned - for many Jeep owners, it's not a one time use thing. I've used both jscan and AlfaOBD several times already and used AlfaODB on my wife's new WK2 to show the dealership about the misfire. I've used the cable, adapter, software, to set tire size, program in the passive entry, program in the auto high beam and stuff I probably have forgotten I did already - oh, to diagnose the brake controller issues months ago before FCA figured out what the issue was.

 

[Terry]

So... I’m sitting at the dealership right now. I asked the service rep to please flash my Speedo to match tire size. He says “We can’t do that anymore. There used to be a code for us to do it but it doesn’t exist anymore. You’ll have to get a device and do it yourself.”

Seriously? Uh... ok. I ask him “How many of your Jeep owners keep stock size tires?” ?

Outside of a Tazer Mini, what other devices exist to do this?

The dealer is spewing BS... I was at my dealer just the other day and spoke directly to the service rep who I personally know about flashing my speedo and the shift points when I go to 35's. He said no problem, we do it just about every day and it costs about $200.00. Get a new dealer.....

 

[Radio Guy]

Hey TYJ, where are you in CA? If your near Los Angeles I have an OBD Jscan setup and for about $20 can add your VIN to the app and you can use my setup to change your tire size.

 

[rickrogan]

YMMV, but I got an AEV ProCal to accomplish the goal. Clearly less functionality than a Tazer, but I didn't want to do a bunch. When I talked to the dealer, they said that was the solution they recommended.

 

[TYJ]

Hey TYJ, where are you in CA? If your near Los Angeles I have an OBD Jscan setup and for about $20 can add your VIN to the app and you can use my setup to change your tire size.

Thanks Radio Guy. Unfortunately I’m about a 12 hour drive away.

 

[TYJ]

The dealer is spewing BS... I was at my dealer just the other day and spoke directly to the service rep who I personally know about flashing my speedo and the shift points when I go to 35's. He said no problem, we do it just about every day and it costs about $200.00. Get a new dealer.....

Next closest dealer to me is a 3 hour drive.

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