From what ive read the major difference between 06 and 07 pcms, are the processors 16 bit in 06 and 32 bit in 07. Arethere any other major differences between the pcms? What are the advantages for switching from 06 to 07 if any?

 

This.

 

Tuning wise, is the 07pcm better or is it just faster?

 

I wouldnt say it's "better" tuning wise than the other year PCM's, but it is an updated OS.

 

Ok thanks for the info

 

I am pretty sure your fuel gauge will be reversed too. Full is empty and empty is full.

 

I think it's more like the 16bit BCM won't be able to read the 32bit registers in the PCM...

You can't just drop in an 07 PCM and expect it to work

Read above...

The 32bit PCM from the 07 can address more memory, but it's not like it matters since there's not enough sensors in an LSJ to need it. I would imagine the processor power is pretty close, but I don't see why you would think that would be relevant; If you think you're going to magically get horsepower by upgrading, you'll be disappointed.

 

I was just pointing it out. You never know.

 

Thanks for the good info and the sarcasm also. I never thought i was going to bolt in and make power. Its going on a mazda bp turbo motor so i can pass obd2 emissions.

 

Hmm, I didnt think the PCM's were swappable between years...? Does make sense from a electronics architecture standpoint that a 16 bit vs 32 bit PCM would swap. Now you claim to be using it on a Mazda engine so that might not make a difference.

 

Well that's usually why people ask that question here, they figure it'll somehow make the car faster. Had you presented the entire problem, you probably would've got a quicker answer.

Well I guess if you don't have to interface with any other controllers it wouldn't be so bad, but I can't see any gains.

 

07 PCM will work. But the fuel gauge does read backwards. I did it.

 

Where is this 16bit vs 32bit stuff coming from? Its the same P12 PCM used on a bunch of other vehicles. The fuel gauge stuff is all just programming. If you flash an 07 PCM with an 06 tune (which in turn would turn the "07 PCM" into an "06 PCM" with corresponding OSID) and install it in an 06, the fuel gauge is not going to read backwards, for instance.

Not saying it couldn't somehow be true, but so far all P12's I've handled have been compatible with all years.

 

It's possible. I never did a full rewrite with that PCM. I put my 05 PCM and all of my tuning has been done with that. I know it does relate to the signal being reversed between the sending units for the different years.

 

Yep, the sending unit is inverted and the scaling in the tune is off.

Now that I stop to think about it, I think I may be approaching it the wrong way. The 07 OS could be 32-bit, just like you can get 32-bit and 64-bit versions of windows and run it on the same hardware.

If thats true though, then why is it still limited to reading 255kPa, etc? The MAP sensor goes all the way to 270kPa, FYI.

I'm still interested in where this info came from though. I think its time to do some digging!

 

Well I guess I stand corrected on this PCM issue apparently, this is interesting for sure...

Woah woah, let's be careful where we go with that. The reason you can run 32bit instructions on 64 bit hardware is because people wanted that capability enough that the processor was built to run both instruction sets. You can't run 16bit software on a 64 bit processor because there's not enough interest, but most of the 32bit processors let you run 16 bit software.

 

It was for comparative purposes, dont read too deep into the 32 vs 64 bit comment. I understand the implications of going "there", sorry. lol

What I'm suggesting is that if the operating systems were in fact different, then the hardware would have to be flexible enough to run each of them.

..and just FYI, the OSes are in fact structured differently, but I can't tell heads or tails whether one is 16 or 32. Just dont have access to that info.

For instance, an 06 OS has transmission stuff and the tables are arranged in a particular order. These tables match the locations for 05 as well.

07 on the other hand has the tables in completely different locations, and the transmission stuff is removed. What filled up the extra room that was left over? Who knows.

This is what I've gleaned from working on the GMS3 project anyway.

 

Yeah I guess they could have 16/32bit processors; Guess we need a tuner to chime in here, and I don't mean a HPTuner lackey or on of those Trifecta guys that send and receiver packages and pose as tuners.

Hard to say if the rewrote their software for 32bit or if buying 16/32bit processors was cheaper in the long run.

 

I put an 06 pcm in my 05 and the fuel gauge was backwards along with the fuel miles remaining. They actually went up as I drove. I did a full rewrite too.

 

^ not sure what to make of that without having been there, but I'm be skeptical as to what tune it was overwritten with. Did you do a read-entire of your original PCM, followed by a write-entire of the new PCM? Did you also unplug the battery on the car before swapping them?

I've run into some "anomalous" stuff when I don't unplug the battery first.

If you pulled an 05 file from somewhere other than your own car, it may have been the reverse-gauge version, since early 05 and late 05 had a different orientation as well. Its really a toss-up sometimes, but I'm convinced that if the OS were 16-bit, or 32-bit, the ONLY difference wouldn't be the orientation and scaling of the fuel gauge. lol