PCM and BCM Swap possibility???

Hi guys,

I was wondering if its possible to swap my PCM and BCM with the intention of the GM dealer flashing from an 02 trailblazer I6 to an 03 trailblazer I6
s Vin OS while at the same time pass the state car inspection with a different Vin number not matched to my registration card? The addin features from an 02 to an 03 trailblazers are about the same so I dont think I will have any electrical problems.

Since I do not think it is possible for efilive to add the feature to adjust the Fuel Gauge amount on the pcm, my intention was to swap to a 03 Vin so that I can obtain the extra fuel package that the 03 trailblazer has that no 02 will ever have. Has anyone with a different Vin ever pass the state inspection?

Thanks

Hate to say it, but why not just use the other software and full flash an 03+ OS into it? If its really in the PCM, that will do it. If not, then change your VIN to an 03 one and have a dealer flash the BCM. Once they flash you'll have to use that VIN otherwise I dont believe the VATS will let the engine start.

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Originally Posted by ScarabEpic22

Hate to say it, but why not just use the other software and full flash an 03+ OS into it? If its really in the PCM, that will do it. If not, then change your VIN to an 03 one and have a dealer flash the BCM. Once they flash you'll have to use that VIN otherwise I dont believe the VATS will let the engine start.

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Thats a good idea but will I be able to pass the state inspection with a different Vin number?

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Originally Posted by goldbergv95

Thats a good idea but will I be able to pass the state inspection with a different Vin number?

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Have to check with your local DMV to answer that one, I dont even know what the rules are in Washington and Ive lived here my whole life.

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Originally Posted by ScarabEpic22

Have to check with your local DMV to answer that one, I dont even know what the rules are in Washington and Ive lived here my whole life.

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Hmm Ill have to ask the dealer later.

I was thinking of purchasing the Tech 2 program. Will this beable to flash the bcm and the pcm?

Yes, I believe you need a yearly subscription to GMs SPS service and its not cheap. I want to say $1000+ a year but its probably more.

Well, I talked to the state inspector and they said this wont be a problem since they dont check the pcm.

But Erik even if I did flash the pcm from an 02 to an 03, the OS would be the same. The updated OS on an 02 is completely different from an 03. I seem to lost the site where they can disclose the pages of OS if the pcm or bcm needs update. Do you remember the site?

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Originally Posted by goldbergv95

Well, I talked to the state inspector and they said this wont be a problem since they dont check the pcm.

But Erik even if I did flash the pcm from an 02 to an 03, the OS would be the same. The updated OS on an 02 is completely different from an 03. I seem to lost the site where they can disclose the pages of OS if the pcm or bcm needs update. Do you remember the site?

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Good to hear, non-issue then.

If you changed the VIN, the OS would be the same. If you upgraded the OS to an 03 one to get the fuel tank calibration, then the OS would be different. Do you know for sure the fuel tank calibration is stored in the BCM or is it stored in the PCM? Figure that out first, then determine if you need to flash the BCM or upgrade the PCM OS to an 03 (go to 05 if you're going to do it).

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Originally Posted by goldbergv95

Well, I talked to the state inspector and they said this wont be a problem since they dont check the pcm.

But Erik even if I did flash the pcm from an 02 to an 03, the OS would be the same. The updated OS on an 02 is completely different from an 03. I seem to lost the site where they can disclose the pages of OS if the pcm or bcm needs update. Do you remember the site?

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http://tis2web.service.gm.com/tis2web
Is this what you want?

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Originally Posted by Jedi_Jr

http://tis2web.service.gm.com/tis2web
Is this what you want?

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YES!!! perfect!!! Thanks a lot!

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Originally Posted by ScarabEpic22

Good to hear, non-issue then.

If you changed the VIN, the OS would be the same. If you upgraded the OS to an 03 one to get the fuel tank calibration, then the OS would be different. Do you know for sure the fuel tank calibration is stored in the BCM or is it stored in the PCM? Figure that out first, then determine if you need to flash the BCM or upgrade the PCM OS to an 03 (go to 05 if you're going to do it).

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Yeah the gm tech 2 is about 2 grand but I heard the software updats is only free for the first 5 months. I might get it since nowadays gm dealers have been pretty busy lately.

Didm't you say the fuel change is stored in the PCM? Regardless, I have to reflash the bcm if I change to the 03 vin or else i would get electric problems. But something still bugs me. Even if I changed the Vin is there a way also change the OS based on the 2003 tbs? Or will I have to get a flash from the dealer.

BTW, I would do a 05 swap but 05s have air bag and other features that 02s and 03s dont have which might fail the state inspection. Plus I saw an additional wire that is connected to a connector located on the exhaust manifold that 02s and 03 dont have.

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Originally Posted by goldbergv95

Didm't you say the fuel change is stored in the PCM? Regardless, I have to reflash the bcm if I change to the 03 vin or else i would get electric problems. But something still bugs me. Even if I changed the Vin is there a way also change the OS based on the 2003 tbs? Or will I have to get a flash from the dealer.

BTW, I would do a 05 swap but 05s have air bag and other features that 02s and 03s dont have which might fail the state inspection. Plus I saw an additional wire that is connected to a connector located on the exhaust manifold that 02s and 03 dont have.

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I assume its in the PCM, but you'd have to figure out where the IPC get the fuel sender signal from.

No, you dont have to flash the BCM if you change the PCM OS, who told you that? Just because you're running an 05 OS doesnt mean you cant put your 02 VIN in...

The airbags and everything dont tie into the PCM...thats not an issue. The 04+s have the AIR injection system on the exhaust manifold so you just have to turn that off in the tune.

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Originally Posted by ScarabEpic22

No, you dont have to flash the BCM if you change the PCM OS, who told you that? Just because you're running an 05 OS doesnt mean you cant put your 02 VIN in...

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Well at least it was not you lol. No really, I thought that was the case from experience. But didnt we had this discussion when I wanted to switch to an 06 ecm with engine wiring, i maybe i was wrong but didnt you think that it might affect the bcm not beable to communitcate efficently? Im a little scared to do the 05 swap unless I do the engine wiring at the same time then I might do it. But for the time being Ill try the 03 first. Then when I have time i might do 06 or possibly 09 swap.

So the only way to change the vin and the os is through the dealer or can i do it?

Ive looked through the pinouts, Im 98% sure the only wiring difference between 02 and 05 are in regards to the AIR system.

To do an 06 swap is just a matter of buying the P12 connectors and pins and wiring it up plus a little tuning, 08-09 E67s means dropping the engine and swapping the crank out.

You can do it with HPT, EFILive doesnt have the full flash P10 capability. Find the latest 05 OS in hpt format, full flash it, then read it out in EFILive and copy your existing tune over.

Doesn't the 05 os have better throttle mapping? If it does I have never seen a differance in any table we have in either HPT or EFILive. I wanted to put an 05 os in to see if it responed better, maybe I will do it now.

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Originally Posted by ScarabEpic22

Ive looked through the pinouts, Im 98% sure the only wiring difference between 02 and 05 are in regards to the AIR system.

To do an 06 swap is just a matter of buying the P12 connectors and pins and wiring it up plus a little tuning, 08-09 E67s means dropping the engine and swapping the crank out.

You can do it with HPT, EFILive doesnt have the full flash P10 capability. Find the latest 05 OS in hpt format, full flash it, then read it out in EFILive and copy your existing tune over.

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So if I did the 05 OS flash, will I get the features that 05 is suppose to get or will I still have the 02 features besides the secondary air injection wire?

Whats the benefit of an 05 rather than just the tune updates?

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Originally Posted by goldbergv95

So if I did the 05 OS flash, will I get the features that 05 is suppose to get or will I still have the 02 features besides the secondary air injection wire?

Whats the benefit of an 05 rather than just the tune updates?

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What do you mean by "features"? You will have whatever an 05 has, fuel tank calibration, fan clutch params, spark tables, etc.

As Jedi_jr said, there are supposed to be driveability improvements made between 02 and 05 that might make a difference.

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Originally Posted by ScarabEpic22

What do you mean by "features"? You will have whatever an 05 has, fuel tank calibration, fan clutch params, spark tables, etc.

As Jedi_jr said, there are supposed to be driveability improvements made between 02 and 05 that might make a difference.

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I mean for the features are the RPOs that comes with an 05. For instance an 03 to 09 has a RPC code called NNK = Extended Fuel Capacity.

I was looking at the difference in wire harness and 04s-06 have the same wires.
http://www.compnine.com/index.php?u=...02&grouptype=B

Quote:

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Originally Posted by ScarabEpic22

Hate to say it, but why not just use the other software and full flash an 03+ OS into it? If its really in the PCM, that will do it. If not, then change your VIN to an 03 one and have a dealer flash the BCM. Once they flash you'll have to use that VIN otherwise I dont believe the VATS will let the engine start.

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So, Eric, if an '05 engine and PCM are swapped into an '04, how come it does not start with the '05 PCM, but starts and runs bad with the '04 PCM? Is it because the BCM needs to be programmed? I am going to try to correct the VIN in the new PCM to see if that helps.

Did you perform the security relearn to link the PCM and BCM?

It should run just fine with the 04 PCM, GM didnt change much between 02-05, 06-07, and 08-09. Change the VIN, but that shouldnt really make much of a difference.

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Originally Posted by ScarabEpic22

Did you perform the security relearn to link the PCM and BCM?

It should run just fine with the 04 PCM, GM didnt change much between 02-05, 06-07, and 08-09. Change the VIN, but that shouldnt really make much of a difference.

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Thanks, does the security relearn to link the PCM and BCM need to be done with a Tech2, or is this possible with my V2 FS?

Since the PCM is from another vehicle, I assume the new PCM needed to be programmed before this security relearn link is attempted?

Worst case scenario, if the new PCM was programmed to the correct VIN and OS, and the security re-learn for the BCM is performed, but it still does not start with the new PCM and starts but runs bad with the old PCM (which appears to be failed - Reduced Power Mode, and the "mechanic" thinks it blew the first engine - what else can I check?

Perhaps I am getting ahead of myself, we'll cross that bridge when I have a look at it this afternoon. Thanks for your advice Erik, I always go to you for TB stuff :good:

Hmmm, you shouldnt have to initiate any security relearn, it should make you do security relearn before it lets you start the vehicle.

Thats really weird, when I ship a PCM the only things that need to be done are a security relearn before it will start then a CASE relearn to ensure misfire detection is correct. I know some people that wait 6 months to do a CASE so it should run just fine without it.

I just finished looking at it and got LOTS of info (tried to start with both PCMs, got codes from both PCMs, saved calibrations from both PCMs).

From the looks of it the old PCM is fried and the new one needs programming.

Are you saying, that if I flash a good calibration into the new PCM (from a different vehicle / VIN) with my Flashscan, it will run fine and not need any BCM programming? I don't recall even being prompted to do any security learn with the V2.

Or, this all needs to be done with the Tech2 / SPS? The code in the new one that won't even crank is "Theft Start Enable Signal Not Correct).

Is the security light on the cluster lit? Thats the security relearn Im talking about. You need to try to start the truck, it shouldnt work but the light will come on. Wait 10-11min, light should go out, try to crank truck again and it shouldnt work, light comes on again. Wait another 10-11min, light should go out, try to crank truck and it should fail again, light comes on. Wait 10-11min, light should go off, try to crank truck and it should work. Basically you're forcing the BCM to learn the new PCM (put the right VIN in the PCM before you do this).

Just flashing it with a Tech II wont bypass this I believe, all used PCMs must go through this.

You cant change the OS in a P10 with EFILive, only a Tech II/Mongoose or HPTuners.

Oh yeah now it's all coming back to me. Thanks! I wonder if that alone would work??

Also, I know you can't full flash these, but can we still cal flash the same and NEWER Cal #s?

The only way to change the cal # is to full flash, so no. If the cal # doesnt match, EFILive wont let you flash it.

Try it out, change the VIN and do the security relearn (try to start, wait 10-11min til light goes out, try again, wait, try, wait, should start).

That is exactly what I plan to do, I appreciate your help! Will let you know tomorrow night

Done :cucumber:

Worked perfect. Thanks again Erik, you helped us out a lot with pointing me in the right direction with this. Everybody's happy.

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Originally Posted by Boost

Done :cucumber:

Worked perfect. Thanks again Erik, you helped us out a lot with pointing me in the right direction with this. Everybody's happy.

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Great! That security relearn is a step some people overlook, anytime you install a used controller in a different vehicle you need to do this procedure. :D

Security relearns for GM vehicles. Identify your system by the key it uses on teh last page of this pdf.

http://www.bsecorp.com/files/techtips/ST9303l.pdf

peace
Hog