PCM DEAD? Wrote C5 LS1edit file into Fbody of same year..dead
11-12-2004, 08:45 PM
#21
TECH Senior Member
Originally Posted by dissonance
did you ever try putting in a y-body?
hardest part about it is removing the flash chip and reinstalling it ... and then having a working PCM afterwards... the flash hardware is pretty standard
11-12-2004, 09:07 PM
#22
putting it into a y body is not going to work, the operating system and the calibration system are two defferent sections.. right now he has a fbody operating system and a corvette cal, with the wrong checksum .. so it doesnt know what to do so there is nothing for you to communicate with inside the pcm to initiate a comunication and upload the instructions needed to flash the chip...\\
a tech 2 will comunicate with anything most of the time when nothing else will.. so if it dont communicate then the only other alternative is a pulled out chip flash.. and.. ive done a bunch and never ruined any, the soldering inst hard as long as you have the right equip
a tech 2 will comunicate with anything most of the time when nothing else will.. so if it dont communicate then the only other alternative is a pulled out chip flash.. and.. ive done a bunch and never ruined any, the soldering inst hard as long as you have the right equip
11-12-2004, 09:10 PM
#23
TECH Senior Member
Originally Posted by wait4me
the soldering inst hard as long as you have the right equip
and skill
I have uber respect for people that can solder ... cause 9/10 times I've tried ... i've ended up melting whatever I was trying to solder... or leaving large blobs of solder hehe
11-12-2004, 10:08 PM
#24
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Originally Posted by horist
and skill I have uber respect for people that can solder ... cause 9/10 times I've tried ... i've ended up melting whatever I was trying to solder... or leaving large blobs of solder hehe
I have uber respect for people that can solder ... cause 9/10 times I've tried ... i've ended up melting whatever I was trying to solder... or leaving large blobs of solder heheYou don't really need to de-solder the flash chips with an iron. Just use a heat gun and gently apply heat while barely lifting the flash chips off the PCB. Once you have them off re-flash them and you can even use a heat gun to re-apply the chips but I always go back over each pin with a soldering iron just to ensure that they make good contact with the pad. You will need to cover the entire PCB in several layers of heavy duty aluminum foil to prevent damage while applying the heat (Except where the chips are being removed). I have a catridge for my Metcal MX-500TS that fits perfectly over the flash chips so it takes me about 5-6 seconds to pop them off and on.
But, I don't have time to do this stuff anymore for the public but if wait4me will do it for you I would jump on it. Otherwise you have a dead pcm that will never work without doing the above process.
11-13-2004, 11:11 AM
#25
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Originally Posted by Slowhawk
If you have a connection at the dealers a new PCM isn't that much.My friend get's them for $160 for me with the right flash in them.You just need a core to give back.$300 with no core.
11-13-2004, 11:14 AM
#26
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Thanks for the offer and everyones helps. (*thanks for the offer wait4me)
A bunch of us were going to order up HPtuners for 98's anyways, so now its a really good time to do it....and im just going to pay the $150 for the new computer at the dealership with my core. Thatll get me back going the fastest i think
A bunch of us were going to order up HPtuners for 98's anyways, so now its a really good time to do it....and im just going to pay the $150 for the new computer at the dealership with my core. Thatll get me back going the fastest i think
11-13-2004, 11:44 AM
#27
I'm told some GM dealers will price match GM Parts direct. A REM 98 PCM is a few dollars cheaper at GM Parts direct, + no tax, but the offset for the tax is $9-10 dollars for shipping. But you still save about $25.00 if the dealer will price match and you don't have to wait on shipping...but more than likely the dealer won't have a 98 in stock either in which case you will have to wait 2-3 days depending on where the GM regional warehouse is.
Nevertheless...ask about price matching.
GM PART # 16238212 for a 98
CATEGORY: Emission Control System Hardware
PACK QTY: 1 CORE CHARGE: $200.00
GM LIST: $230.37
OUR PRICE: $115.19
DESCRIPTION: PCM REM
Nevertheless...ask about price matching.
GM PART # 16238212 for a 98
CATEGORY: Emission Control System Hardware
PACK QTY: 1 CORE CHARGE: $200.00
GM LIST: $230.37
OUR PRICE: $115.19
DESCRIPTION: PCM REM
Last edited by dlandsvZ28; 11-13-2004 at 11:53 AM.
11-13-2004, 10:27 PM
#29
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What did the tech2 say?
What steps did the guy take? Did he try to read the pcm with the tech2 1st? And it said it was unable to communicate with the pcm?
Then did he take the original VIN and download the program for that PCM? Off GM tech site?
If he did all of this, did he then hook it back up and still said something like unable to communicate “there should be an option at that point to force a reprogram.
Now to get to the y-body thing, the flash chip has a low level communication that should allow a flash. Just because the CRC “check sum” does not match does not mean you can’t communicate with the chip itself… this is how GM does it at the factory. I would not give up on that PCM just let, also if it did come down to removing the chip from the PCB you don’t really have to remove it… you have other options. So does GM order the Intel flash already flashed with VIN and CAL from Intel? No they don’t… they program each one... how do they program a million blank pcm?
If you’re still unsure I will buy the old PCM from you if you do chose to buy a new one, that’s how confident I’m it can be recovered.
What steps did the guy take? Did he try to read the pcm with the tech2 1st? And it said it was unable to communicate with the pcm?
Then did he take the original VIN and download the program for that PCM? Off GM tech site?
If he did all of this, did he then hook it back up and still said something like unable to communicate “there should be an option at that point to force a reprogram.
Now to get to the y-body thing, the flash chip has a low level communication that should allow a flash. Just because the CRC “check sum” does not match does not mean you can’t communicate with the chip itself… this is how GM does it at the factory. I would not give up on that PCM just let, also if it did come down to removing the chip from the PCB you don’t really have to remove it… you have other options. So does GM order the Intel flash already flashed with VIN and CAL from Intel? No they don’t… they program each one... how do they program a million blank pcm?
If you’re still unsure I will buy the old PCM from you if you do chose to buy a new one, that’s how confident I’m it can be recovered.
Last edited by dissonance; 11-13-2004 at 11:07 PM.
11-13-2004, 11:32 PM
#30
I went through the exact same circumstance. The dealer tried to reflash my PCM and couldn't, charged me the $90 flat fee and proceeded to start to order a new pcm (but I was lucky...the tuner who tried to reflash it had to buy me a new one).
Nevertheless, I tend to agree with you that the chip that everyone speaks of that gets hosed can be reflashed rather than unsoldered...but that's just my humble opinion.
No offense to dealers and their techs, but IMO a dealer's policy with respect to defective PCMS is somewhat like IT tech departments and that is "it's cheaper to replace parts and software than it is to diagnose and solve the problem". I suspect this chip get 'fried' same as the Bios chip on a motherboard does, but it quicker/cheaper to replace the entire pc rather than the chip or the motherboard.
I recall reading in another thread that PCM for Less agrees that most PCMS can be reflashed rather than desoldering the chip.
I guess it's the 'how is it done?' that is the illusive secret.
Or it's GM's policy that it can replace the board in the PCM cheaper than the costs it would incur to desolder the chip and reflash it.
Considering the fact that cheap PC motherboards retail for as little as $39 we know that the board in a PCM costs considerably less since GM buys millions of them (probably a dollar or two for the board).
So at $90 an hour it cheaper to tell the customer the PCM is bad, charge them $230 for a new PCM and send them on their way.
And the fact that LS1 backyard mechanics sometimes 'fry' the pcm...it's probably GM's opinion that we shouldn't have been messing with the pcm in the first place. We play...then sometimes we gotta pay.
You might check out this site
http://www.madz28.com/repair.php
Nevertheless, I tend to agree with you that the chip that everyone speaks of that gets hosed can be reflashed rather than unsoldered...but that's just my humble opinion.
No offense to dealers and their techs, but IMO a dealer's policy with respect to defective PCMS is somewhat like IT tech departments and that is "it's cheaper to replace parts and software than it is to diagnose and solve the problem". I suspect this chip get 'fried' same as the Bios chip on a motherboard does, but it quicker/cheaper to replace the entire pc rather than the chip or the motherboard.
I recall reading in another thread that PCM for Less agrees that most PCMS can be reflashed rather than desoldering the chip.
I guess it's the 'how is it done?' that is the illusive secret.
Or it's GM's policy that it can replace the board in the PCM cheaper than the costs it would incur to desolder the chip and reflash it.
Considering the fact that cheap PC motherboards retail for as little as $39 we know that the board in a PCM costs considerably less since GM buys millions of them (probably a dollar or two for the board).
So at $90 an hour it cheaper to tell the customer the PCM is bad, charge them $230 for a new PCM and send them on their way.
And the fact that LS1 backyard mechanics sometimes 'fry' the pcm...it's probably GM's opinion that we shouldn't have been messing with the pcm in the first place. We play...then sometimes we gotta pay.
You might check out this site
http://www.madz28.com/repair.php
Last edited by dlandsvZ28; 11-14-2004 at 12:06 AM.
11-14-2004, 12:37 AM
#31
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Here's some info on the in's and out's of reflashing and why stuff happens and what can be recovered and what can't.
In all cases below the PCM reflashing process consists of the following:
1. initialisation
2. erase flash commands (either entire flash chip or a section of it)
3. write flash commands (sending the new data to the erased flash chip)
4. some checks at the end
5. PCM reset
It is important to realise that the flash chip memory is arranged into usually 6-12 "banks" that can be erased, you can't erase a single byte and then write it with the new data. Likewise, you can't just write the new data without first erasing.
99+ V8 multi segment binaries
The PCM software is split into 2 main parts:
- the Operating System (think - Windows XP)
- the Calibration section (think - your files)
Also, the calibration section fits nicely into a single flash bank that is easily erased without erasing the oparting system parts.
When you reflash the PCM generally most software out there only reflashes the calibration section and leaves the operating system alone. This procedure is totally safe and is probably the reason GM moved to these multisegment binaries and postioned them in the flash chip so that this section can be erased and written without the need to rewrite anything else.
If you get a calibration write failure generally the PCM goes into "bootstrap" mode, where it just sits there saying "start downloading a calibration cos my current one is screwed" - tech2 and our software identifies this mode and lets you flash. Note: when the PCM is in this mode it will not respond to PID requests asking for VIN#'s, serial #'s or anything else you can think of (there's a hint as to why the other guys wont let you flash - and tell you the PCM is "fried" which is a load of...). The PC analogy here is you just erased all your files on your PC and you want to reload them again from a CD backup. Since WinXP is still working you just put the CD in and copy them over...
Now, we also allow you to rewrite the entire PCM Operating system and calibration. Here's where things are not so safe. Imagine on your PC you just backed up all your files *and* your operating system to a CD creating an "image" of your harddisk. Now you typed "format C:" thinking you can just put that CD back in and restore your system. Uh oh, your CD drive doesn't work anymore without windows loaded does it? Same with the PCM, you can't flash via the OBD2 port if the PCM operating system isn't there to make the OBD2 port work. The big differnce here is with a PC you have a BIOS and you can just make a bootable CD or floppy and start loading your operating system again. On the PCM this mechanism doesn't exist and it's time to desolder the flash chip. That's why it is very important that you never power down your PCM if you have a write failure on an entire PCM rewrite, you can reboot your machine, retest you cables etc. to try and fix the issue, but never power down the PCM.
98's and other single segment binaries
Now, for 98's and V6 vehicles (and others) the binary file is not neatly segmented as i described above, it's all in one big blob. Also, the calibration section is not nicely alined into a flash bank, to erase the calibration you must erase all or some of the operating system.
A lot of software, including tech2, rewrites the entire PCM flash, operating system + calibration. It's obviously a more dangerous process as i described in the latter section above. We have devised ways around this shortcoming and is the reason that all our V6 and 98 V8 customers can reflash with far more confidence than even tech2. Again, it is very important that if the software you use does erase and then rewrite the entire PCM flash - never power down your PCM unless you want to get out your soldering iron...
I hope that helps explain a few things.
Cheers,
Chris...
In all cases below the PCM reflashing process consists of the following:
1. initialisation
2. erase flash commands (either entire flash chip or a section of it)
3. write flash commands (sending the new data to the erased flash chip)
4. some checks at the end
5. PCM reset
It is important to realise that the flash chip memory is arranged into usually 6-12 "banks" that can be erased, you can't erase a single byte and then write it with the new data. Likewise, you can't just write the new data without first erasing.
99+ V8 multi segment binaries
The PCM software is split into 2 main parts:
- the Operating System (think - Windows XP)
- the Calibration section (think - your files)
Also, the calibration section fits nicely into a single flash bank that is easily erased without erasing the oparting system parts.
When you reflash the PCM generally most software out there only reflashes the calibration section and leaves the operating system alone. This procedure is totally safe and is probably the reason GM moved to these multisegment binaries and postioned them in the flash chip so that this section can be erased and written without the need to rewrite anything else.
If you get a calibration write failure generally the PCM goes into "bootstrap" mode, where it just sits there saying "start downloading a calibration cos my current one is screwed" - tech2 and our software identifies this mode and lets you flash. Note: when the PCM is in this mode it will not respond to PID requests asking for VIN#'s, serial #'s or anything else you can think of (there's a hint as to why the other guys wont let you flash - and tell you the PCM is "fried" which is a load of...). The PC analogy here is you just erased all your files on your PC and you want to reload them again from a CD backup. Since WinXP is still working you just put the CD in and copy them over...
Now, we also allow you to rewrite the entire PCM Operating system and calibration. Here's where things are not so safe. Imagine on your PC you just backed up all your files *and* your operating system to a CD creating an "image" of your harddisk. Now you typed "format C:" thinking you can just put that CD back in and restore your system. Uh oh, your CD drive doesn't work anymore without windows loaded does it? Same with the PCM, you can't flash via the OBD2 port if the PCM operating system isn't there to make the OBD2 port work. The big differnce here is with a PC you have a BIOS and you can just make a bootable CD or floppy and start loading your operating system again. On the PCM this mechanism doesn't exist and it's time to desolder the flash chip. That's why it is very important that you never power down your PCM if you have a write failure on an entire PCM rewrite, you can reboot your machine, retest you cables etc. to try and fix the issue, but never power down the PCM.
98's and other single segment binaries
Now, for 98's and V6 vehicles (and others) the binary file is not neatly segmented as i described above, it's all in one big blob. Also, the calibration section is not nicely alined into a flash bank, to erase the calibration you must erase all or some of the operating system.
A lot of software, including tech2, rewrites the entire PCM flash, operating system + calibration. It's obviously a more dangerous process as i described in the latter section above. We have devised ways around this shortcoming and is the reason that all our V6 and 98 V8 customers can reflash with far more confidence than even tech2. Again, it is very important that if the software you use does erase and then rewrite the entire PCM flash - never power down your PCM unless you want to get out your soldering iron...
I hope that helps explain a few things.
Cheers,
Chris...
11-14-2004, 01:09 AM
#32
Thanks for a clearer explanation.
Can you explain what you mean by the PCM is 'powered down'? Would that be like when the battery goes dead, laptop battery dies, I turn the key off, fuse blows etc.?
Finally, any ideas why the Vinci handheld can read and flash so quickly and appears to be crash free. It's fast, that's for sure.
Can you explain what you mean by the PCM is 'powered down'? Would that be like when the battery goes dead, laptop battery dies, I turn the key off, fuse blows etc.?
Finally, any ideas why the Vinci handheld can read and flash so quickly and appears to be crash free. It's fast, that's for sure.
11-14-2004, 04:53 AM
#33
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Originally Posted by dlandsvZ28
Thanks for a clearer explanation.
Can you explain what you mean by the PCM is 'powered down'? Would that be like when the battery goes dead, laptop battery dies, I turn the key off, fuse blows etc.?
Finally, any ideas why the Vinci handheld can read and flash so quickly and appears to be crash free. It's fast, that's for sure.
Can you explain what you mean by the PCM is 'powered down'? Would that be like when the battery goes dead, laptop battery dies, I turn the key off, fuse blows etc.?
Finally, any ideas why the Vinci handheld can read and flash so quickly and appears to be crash free. It's fast, that's for sure.
Never used or seen a da vinci so can't comment, we read the whole 512k or 1024k flash image in about 2 or 4mins and flash the cal in about 30secs (which is as fast as the class2 bus will let you go).
11-14-2004, 08:04 PM
#34
nice info game over that really makes things easier for people to understand, i normally just have them send me the pcm to pull the flash "if its a 97 or 98" when they over write it like he did, i do it for free, just to help guys out.. its a pain, but fun... jes
that really makes things easier for people to understand, i normally just have them send me the pcm to pull the flash "if its a 97 or 98" when they over write it like he did, i do it for free, just to help guys out.. its a pain, but fun... jes 