Speedo fiddle bricked PCM, need flash location
01-05-2017, 01:48 PM
#1
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Thread Starter
Speedo fiddle bricked PCM, need flash location 12589462 1MB PCM.
Sure HPTuners has a warning about low numbers here. I didn't think 1700 was that low. Flashed the tune and now the PCM crashes on power up and restarts which runs the fuel pump relay at about 100Hz. Will no longer respond via OBD2.
I don't want to get a replacement ECU and pay for more credits.
Anyway, I have the ability to remove the flash chip and program it.
The problem is I need to know where in flash to correct the speed output value.
I could flash a stock tune back in, but that would change the VIN and I'd still have to buy more credits for HP tuners to work with it.
Tunerpro has XDFs floating around for the 0411 512k PCMs but I haven't seen anything for the 1MB PCMs.
Can anyone help with either an XDF or the flash location of the value for Speedometer->Calibration->PCM Output Calibration->Pulses per mile?
Or suggest some other way to fix the PCM?
Sure HPTuners has a warning about low numbers here. I didn't think 1700 was that low. Flashed the tune and now the PCM crashes on power up and restarts which runs the fuel pump relay at about 100Hz. Will no longer respond via OBD2.
I don't want to get a replacement ECU and pay for more credits.
Anyway, I have the ability to remove the flash chip and program it.
The problem is I need to know where in flash to correct the speed output value.
I could flash a stock tune back in, but that would change the VIN and I'd still have to buy more credits for HP tuners to work with it.
Tunerpro has XDFs floating around for the 0411 512k PCMs but I haven't seen anything for the 1MB PCMs.
Can anyone help with either an XDF or the flash location of the value for Speedometer->Calibration->PCM Output Calibration->Pulses per mile?
Or suggest some other way to fix the PCM?
01-06-2017, 04:57 PM
#2
Anyway, I have the ability to remove the flash chip and program it.
The problem is I need to know where in flash to correct the speed output value.
I could flash a stock tune back in, but that would change the VIN and I'd still have to buy more credits for HP tuners to work with it.
01-06-2017, 09:05 PM
#4
Teching In
Thread Starter
This is not a 0411 PCM. If it was then I could just use Tunerpro and the available XDFs to edit a bin to work out the flash location I need to update.
This is a 05 DBW truck PCM with a 1MB flash chip. The 0411s used a 512k.
In any case for either PCM the flash is not socketed. I'll do some hot air rework to pull the chip. It's a SOP44 AM29F800BB-70SE to be exact.
The chip itself is not bad, so no need to replace it with another. The problem is that for some configuration values (mainly speedo output and ETC values from what I have seen) the operating system does no sanity checking. And so if you set them to a bad value (too low in the speedo output case) then the OS crashes on startup and you don't get a chance to reflash to a good value via OBD2.
So the very kind Mr MontecarloDrag will likely flash a good version of my tune using HP tuners to an PCM he has, read it back with something else to get the bin file.
I'll desolder and program that bin file into my flash chip and solder it back into my PCM. That should see it fixed.
This is a 05 DBW truck PCM with a 1MB flash chip. The 0411s used a 512k.
In any case for either PCM the flash is not socketed. I'll do some hot air rework to pull the chip. It's a SOP44 AM29F800BB-70SE to be exact.
The chip itself is not bad, so no need to replace it with another. The problem is that for some configuration values (mainly speedo output and ETC values from what I have seen) the operating system does no sanity checking. And so if you set them to a bad value (too low in the speedo output case) then the OS crashes on startup and you don't get a chance to reflash to a good value via OBD2.
So the very kind Mr MontecarloDrag will likely flash a good version of my tune using HP tuners to an PCM he has, read it back with something else to get the bin file.
I'll desolder and program that bin file into my flash chip and solder it back into my PCM. That should see it fixed.
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05-27-2017, 12:43 PM
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This is not a 0411 PCM. If it was then I could just use Tunerpro and the available XDFs to edit a bin to work out the flash location I need to update.
This is a 05 DBW truck PCM with a 1MB flash chip. The 0411s used a 512k.
In any case for either PCM the flash is not socketed. I'll do some hot air rework to pull the chip. It's a SOP44 AM29F800BB-70SE to be exact.
The chip itself is not bad, so no need to replace it with another. The problem is that for some configuration values (mainly speedo output and ETC values from what I have seen) the operating system does no sanity checking. And so if you set them to a bad value (too low in the speedo output case) then the OS crashes on startup and you don't get a chance to reflash to a good value via OBD2.
So the very kind Mr MontecarloDrag will likely flash a good version of my tune using HP tuners to an PCM he has, read it back with something else to get the bin file.
I'll desolder and program that bin file into my flash chip and solder it back into my PCM. That should see it fixed.
This is a 05 DBW truck PCM with a 1MB flash chip. The 0411s used a 512k.
In any case for either PCM the flash is not socketed. I'll do some hot air rework to pull the chip. It's a SOP44 AM29F800BB-70SE to be exact.
The chip itself is not bad, so no need to replace it with another. The problem is that for some configuration values (mainly speedo output and ETC values from what I have seen) the operating system does no sanity checking. And so if you set them to a bad value (too low in the speedo output case) then the OS crashes on startup and you don't get a chance to reflash to a good value via OBD2.
So the very kind Mr MontecarloDrag will likely flash a good version of my tune using HP tuners to an PCM he has, read it back with something else to get the bin file.
I'll desolder and program that bin file into my flash chip and solder it back into my PCM. That should see it fixed.
Any chance you want to do a write up on how to do this? I just bricked the same pcm you have and would like to avoid buying a new pcm and credits.
How do you program the flash chip if its not in the pcm? I have a .bin file for my pcm that i could revert back to if needed.
05-27-2017, 12:50 PM
#10
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Thread Starter
You'll need a programmer that can take PSOP44 chips.
Something like this:
Honestly the soldering is the hardest part.
If you want you can mail me the flash chip and I'll program it for you. PM me.
Something like this:
Honestly the soldering is the hardest part.
If you want you can mail me the flash chip and I'll program it for you. PM me.
05-27-2017, 01:12 PM
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You'll need a programmer that can take PSOP44 chips.
Something like this:
https://www.amazon.com/Prg-108-GQ-4X...dp/B0121LD5VQ/
Honestly the soldering is the hardest part.
If you want you can mail me the flash chip and I'll program it for you. PM me.
Something like this:
https://www.amazon.com/Prg-108-GQ-4X...dp/B0121LD5VQ/
Honestly the soldering is the hardest part.
If you want you can mail me the flash chip and I'll program it for you. PM me.
Just for clarification I would put the flash chip in there and load my complete bin file on it? Or would it need to be an edited bin some how? Will that particular model in the link work for what i need?
Thanks for the help!
05-27-2017, 01:25 PM
#12
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Thread Starter
Yes that programmer will work.
Desolder your flash chip.
Put it in the programmer.
Read your bad tune out. Save it.
Check to make sure that your existing .bin looks nearly identical in a hex editor.
Note that byte ordering can mess with things. The CPUs in these GM PCMs use Big Endian while PCs use Little endian. Most programmer software had the option to byte swap for you. Sometimes it tries to be too clever and auto byte swaps which can be a pain. Go google endianess & read up if you are confused. Your EE friends should know all about it too.
Burn you old .bin into the flash.
Read it back out and make sure it looks pretty similar to the bad one you read out above (i.e. make sure the bytes are in the right order).
Solder the chip back in and you should be good to go.
I sometimes have trouble with these PSOP44 chips. If a pin is tweaked then it can stop others from making proper contact in the programmer. So if you have trouble reading/writing straighten and clean up the pins.
Desolder your flash chip.
Put it in the programmer.
Read your bad tune out. Save it.
Check to make sure that your existing .bin looks nearly identical in a hex editor.
Note that byte ordering can mess with things. The CPUs in these GM PCMs use Big Endian while PCs use Little endian. Most programmer software had the option to byte swap for you. Sometimes it tries to be too clever and auto byte swaps which can be a pain. Go google endianess & read up if you are confused. Your EE friends should know all about it too.
Burn you old .bin into the flash.
Read it back out and make sure it looks pretty similar to the bad one you read out above (i.e. make sure the bytes are in the right order).
Solder the chip back in and you should be good to go.
I sometimes have trouble with these PSOP44 chips. If a pin is tweaked then it can stop others from making proper contact in the programmer. So if you have trouble reading/writing straighten and clean up the pins.
09-18-2018, 05:30 AM
#15
Not to beat a dead horse... but I believe your the right fellas to ask. I have a licensed pcm with hptuners that was in a small garage fire and got cooked. I'm able to access it and read and write. But it wont run my engine anymore... I'm guessing bad solder joint or something... can I take the flash chip out and swap into a similar pcm and not have to buy more credits with hptuners?
09-18-2018, 09:48 AM
#16
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Curtis Buechler (04-12-2020)
09-27-2018, 06:49 PM
#17
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Monte, I’m very impressed with your knowledge of this process. I have one more question for you, if someone took and flashed their prom with the v8 parameters and installed it in a computer originally tuned for a v8 would it skip having to have the computer unlocked by a tech2 and flashed with the v8 information?
