Reprograming the speedometer for larger tires.

[Hum2]

All:

My dealer says it is not possible to reprogram the H2 computer (speedometer) if you add on larger diameter wheels. Anyone have info on this?

Ric
OMAHOG/IHOG

OMAHOG/IHOG
Hum2@cox.net

[BADRAP]

Klaus, if you do that in a GM truck it will kick on the ABS sensor, and the Check engine light. Trust me have been there and tried that, it does not work.....

BADRAP
03 H2, Lux, Pewter, Granatelli Diablo Programmer, Airaid intake, TB Spacer, more stuff soon..
H2 Club - Houston Chapter..
badrap@sbcglobal.net

[Hum2]

Thanks kdio:

That would mean the dealer would have to buy the programer....ha ha! I think for that price I will have to live with the variance in the speedo.

Ric

OMAHOG/IHOG
Hum2@cox.net

[Hummie2]

Klaus...

Maybe, but don't know if that will work with trac control and anti-skid sensors at wheels though. Might be too much variance for them to work properly.

Don

[Hummie2]

<BLOCKQUOTE class="ip-ubbcode-quote"><font size="-1">quote:</font><HR> posted 06-20-03 07:18 AM
All:

My dealer says it is not possible to reprogram the H2 computer (speedometer) if you add on larger diameter wheels. Anyone have info on this?

Ric
OMAHOG/IHOG


<HR></BLOCKQUOTE>

This is quoted per the H2 Manual Supplement for the predator programer:

" Note regarding tire sizes:

Due to the fact that the factory PCM can only compute for a limited range of tire sizes and can not reclabritate for extremely oversized tire/wheel combinations. Please take note of this if the entered tire aspect ratio does not recalibrate the speedometer, you are most likely over the size limit."

Sounds like it might be a hit or miss situation here.

Don

[kdio]

Not true. If you buy a after market programmer it is easily done. Proflash and Predator make a power programmer for the H2. The range in price from $320 to $550.

03 H2 Sunset Orange Polished Magna Charger w headers & cold air intake, 37" MTRs w Weld Mountain Crushers, GPS Nav. & 2 rear LCD TVs w DVD, Extreme Tube steps

[TheGoodHummerMan]

After checking my H2's speedo / odometer, it seems to be reading incorrectly, with the stock BFG tires.

It is indicating that the speed is between 1 and 2 mph higher than what the GPS reports and about 1% higher in mileage too.

Is this even significant or, as I suspect, well within "normal" variances for seedometers?

Ed

[whipplecharged]

One reason is the dealer likes to scare people and tell them if they change anything it will void the warranty.The dealer can even do it themself with the tech 2 scanner they have. But usually the salesmen or service writer do not know it. Reprogramming for different tires has been done for years. When they went to the OBD II ECU's in 96 Flash programming was the only way to make those kind of changes.

[TheGoodHummerMan]

kdio,

How does the adjustment for different sized tires work? Do you adjust the speedo by percentages? Reason I ask is that my stock odometer seems to be reading "off" by about 1% which, as I mentioned earlier, is NOT a big deal... But, could this small of an adjustment be made with the programmer?

Thanks, Ed

[Hum2]

All:

My dealer says it is not possible to reprogram the H2 computer (speedometer) if you add on larger diameter wheels. Anyone have info on this?

Ric
OMAHOG/IHOG

OMAHOG/IHOG
Hum2@cox.net

[Klaus]

If the tire size is too large for the programmer/computer, you might be able to "fool" the system by inputing a higher (lower numerically) rear axle ratio instead.

Klaus

"God made some men big and some men small, but Sam Colt made them all equal."

[kdio]

I had the Proflash programmer, and it allowed for 44 inch tires. So unless you are putting on a huge lift kit, these programmer can handle your larger tires. I have 37 inch tires and the programmer was able to reprogram my speedo no problem. You also get the added benefit of increase performance and better fuel ecomony.

03 H2 Sunset Orange Polished Magna Charger w headers & cold air intake, 37" MTRs w Weld Mountain Crushers, GPS Nav. & 2 rear LCD TVs w DVD, Extreme Tube steps