i'm not so sure about that...usually firmware/software upgrades only result in different version numbers not part numbers. take the ipod for instance...my ipod still has the same part number as the day i bought it (over a year ago) but the firmware has been upgarded multiple times and not the firmware VERSION number reads different than the day i purchased it. same goes for my PS3 and for people with older 2IS who upgrade the nav...they still have the same nav part number but different software VERSION....just my .02

 

Yes, that is correct. However, flashing the ECU in the field is different than replacement parts. For example, If, for some reason, you needed to *replace* your ECU, the new programming of ECU's in stock would carry a new part number.

 

From a manufacturing/inventory perspective it'd make a LOT more sense to have -one- part and have the tech in the field flash any relevant updates/changes specific to the model and year when he installs the unit... rather than keep separate inventory for multiple flash revisions and years.

 

Yes, that is true, also. But, if the programming revision is also made on production cars coming out of the factory, the production parts with the revision will have a new part number. If Lexus does not incorporate the revision on production cars and only allows for field programming, the part number will not change.

 

I can only speak to computer manufacturing but they still flash it in manufacturing, rather than having multiple part numbers for the same physical part. During assembly they just load (for PCs) the relevant image for the unit being built during the build process... no reason they couldn't do that with cars, given how little time flashing an ECU takes, and how much time/hassle that'd save compared to multiple part numbers for the same physical part.

Just thinking out loud though...

Hrm... the IS350 and GS350 have the same engine, but I'd imagine have different engine programming... do they use the same part number for the engine ECU?

Several folks who previously were unaware of a supposed steering change on 08s have commented on it though, so I've got to think -something- changes.. and the code in the steering ECU would be the "simplest" thing.

 

the o8 is awd feels alot lighter than my 07 awd

 

It's a good thought. Unfortunately, that's not how it works. Here's a scenario:

My 2008 IS350 just smoked the power steering ECU. They order a new one under warranty, which happens to be the same part number as the 2007. Since my car is a 2008 do they have to flash the ECU to update it to the 2008 programming?

Nope. In my 28 years with Lexus/Toyota, I've never heard of that happening. There's something else different about the 2008 system. When Lexus says that the 2008 is "calibrated" for better steering feel, well, that could be something as simple as a change in the alignment specs. Also, I did some more research and discovered that the intermediate steering shaft on 2008 is different than 2006-2007 models. Maybe *that* has something to do with it.

I'll continue to do more research to find out what Lexus did to "recalibrate" the system for 2008.

 

In addition to the intermediate shaft, front and rear springs are different. Also, the front sway bar bracket has been redesigned. Still searching.

 

can we just go to the dealer and ask them to tighten our steering?

 

Yeah I've noticed after driving a lady friend's 08 IS250 the difference from my old 07 IS350 and after commenting on the steering feeling a lot more tighter (more Audi than BMW) she said that the car salesman mentioned that Lexus changed the steering ratios for 08.

 

This man speaks the truth. Sure there are a lot of ways other companies address software updates. Lexus/Toyota/Scion do it ONE way - new part number. How do I know? The same way IS350Jet knows - experience.

Remember when I tried the '07 skid control computer in my '06 to see if the VSC off functionality would work with an otherwise unmodified '06 IS350? Well, not only did it work, but I found out if I were to have an issue with the '06 skid control computer, I'd get the '07 as an updated part because the '06 skid control computer has been superceded by the '07 and later. It has a completely different part number, but it's plug n' play. So, if there isn't a new part number for the steering ECU, it is unchanged for both hardware and software. The changes had to be made somewhere else.

 

Is there already more information about the steering wheel difference between the 06-07 vs 08+

Maybe some 08 owners could switch the powersteering ECU with 06 owners in order to compare? This is the most easiest and pratical way to test it.

 

Found a 2008 steering ecu, so I am going to replace it in my 2006 as soon as I get it, keep u guys posted!

 

would the ISF steering dampner help the loose feel in my 06 -- granted I think it is not too bad, but I have an AWD. If not what would the dampner do..... I have one sitting at the house I have not installed yet.

 

08+ cars as on, the steering is different because the steering wheel had been recalibrated for better feel.

http://www.edmunds.com/lexus/is-250/2008/

Most likely ECU because I felt the difference between 07 AWD I had and 09 AWD. Also felt differences in the RWD ones too.