TripleTransAm
08-13-2003, 10:20 AM
Had a long chat with my favorite tech regarding PCM software codes and calibrations and all that jazz.
Here's the digested version, and let me tell you it ain't pretty. A lot of us had partial info that was correct but to get the big picture you need to put it all together and infuse it with a dash of Ford bureaucracy to give it the final flavor. Obviously I cannot vouch for the accuracy of the info, but I have had no reason to doubt the info that I've received from this technician in the past. So here goes:
First off, the sticker with the 4 character code (CRD1, etc.etc.) is referred to as a 'tear tag'. It's literally 'torn' from the sticker that is supposedly on the PCM box itself. What it denotes is the overall 'package' that comprises your PCM hardware and software and calibrations. It's what your car was born with (I use this term because we'll use it again later).
The example we discussed:
Over the course of the vehicle lifespan, new calibrations are released to address driveability issues, etc. So using a Marauder as an example, a car that was built in mid 2002 might come with a FDH2 tear tag code. If it's stock and untouched, it will have the calibrations it left the factory with. Take a car that was built in Feb 2003 and it might have a tear tag of CRD1. Chances are it has a different set of calibrations.
Now in our example, the FDH2 car might get a new set of calibrations issued specifically for it. Let's say there is NO update to the CRD1 s/w as well. Why doesn't the same upgrade apply to the CRD1 that applies to the FDH2? One example was that the FDH2 might have been released at a time when certain options were not available (traction control, etc.) or that the car was built at a date where certain different emissions guidelines were in effect, and therefore these calibrations cannot (by law) be loaded on a car built at a later date.
According to the tech, the implementation of these codes is Ford's way of making sure calibration revisions only get loaded on the PCMs they were intended to be loaded on.
It can actually happen that PCM calibrations and codes end up becoming completely identical, and yet they won't share the same part numbers or tear tag codes. As a fictitious (but possible) example, the FDH2 car can receive an updated calibration s/w, and if you compare bit-for-bit it may actually end up looking completely identical to the CRD1 code. However, for configuration management reasons, it appears they can never be called the same part number... the code to be loaded for FDH2 cars must always be distinguishable from that in the CRD1 cars, simply because they were born with that tear tag.
At the same time, the tech hinted that it would probably be possible to load FDH2 code into a PCM originally born as a CRD1 car and it would probably run identical as on a car originally an FDH2 (although you'd need to fudge the flasher into allowing this upload to be accepted).
What we did not discuss (due to time constraints) was the existence of all those extra tear tag codes mentioned in another thread... we still only saw 4 codes (CRD0, CRD1, BMD0, FDH2) and their corresponding calibration part number. Also, I did not bring up the possibility of flashing the actual s/w (not just calibrations as is the case with chips and tuners), I'll discuss this at my next visit in a week's time.
So what all this seems to generate is a tree of revisions, some of which might actually be completely identical, ie:
FDH2 series might spawn 3 updated calibrations, BMD0 might have 1 additional new calibration (which could be identical to the 2nd update for FDH2), CRD1 might only have 1 existing calibration (that might be identical to the 3rd update for FDH2), etc.... all fictitious examples, but meant to illustrate how the existence of dozens of part numbers for calibrations doesn't mean there are dozens of unique calibrations.
After having this discussion, I can now see where it might be possible to have so many software revisions out there for Ford PCMs. A mention was made of 12000 in total... I think I can believe that, since looking at a model like our Marauder, just the fact of having 4 different 'packages' leave the ***embly line over the course of a model year means that even one update that is common to all 4 'packages' will generate 4 parts numbers.
Hope this makes sense. It was a long convoluted discussion involving pen and paper and lots of scribbling to try and make sense of this method of software configuration management. Please feel free to poke holes in all this, I'll deliver whatever remaining uncertainties we have to the technician next time we meet (within 2 weeks, for sure).
In case Terrebonne Ford's Eric Aumont is reading this, thanks for taking the time this morning to explain all this.
Here's the digested version, and let me tell you it ain't pretty. A lot of us had partial info that was correct but to get the big picture you need to put it all together and infuse it with a dash of Ford bureaucracy to give it the final flavor. Obviously I cannot vouch for the accuracy of the info, but I have had no reason to doubt the info that I've received from this technician in the past. So here goes:
First off, the sticker with the 4 character code (CRD1, etc.etc.) is referred to as a 'tear tag'. It's literally 'torn' from the sticker that is supposedly on the PCM box itself. What it denotes is the overall 'package' that comprises your PCM hardware and software and calibrations. It's what your car was born with (I use this term because we'll use it again later).
The example we discussed:
Over the course of the vehicle lifespan, new calibrations are released to address driveability issues, etc. So using a Marauder as an example, a car that was built in mid 2002 might come with a FDH2 tear tag code. If it's stock and untouched, it will have the calibrations it left the factory with. Take a car that was built in Feb 2003 and it might have a tear tag of CRD1. Chances are it has a different set of calibrations.
Now in our example, the FDH2 car might get a new set of calibrations issued specifically for it. Let's say there is NO update to the CRD1 s/w as well. Why doesn't the same upgrade apply to the CRD1 that applies to the FDH2? One example was that the FDH2 might have been released at a time when certain options were not available (traction control, etc.) or that the car was built at a date where certain different emissions guidelines were in effect, and therefore these calibrations cannot (by law) be loaded on a car built at a later date.
According to the tech, the implementation of these codes is Ford's way of making sure calibration revisions only get loaded on the PCMs they were intended to be loaded on.
It can actually happen that PCM calibrations and codes end up becoming completely identical, and yet they won't share the same part numbers or tear tag codes. As a fictitious (but possible) example, the FDH2 car can receive an updated calibration s/w, and if you compare bit-for-bit it may actually end up looking completely identical to the CRD1 code. However, for configuration management reasons, it appears they can never be called the same part number... the code to be loaded for FDH2 cars must always be distinguishable from that in the CRD1 cars, simply because they were born with that tear tag.
At the same time, the tech hinted that it would probably be possible to load FDH2 code into a PCM originally born as a CRD1 car and it would probably run identical as on a car originally an FDH2 (although you'd need to fudge the flasher into allowing this upload to be accepted).
What we did not discuss (due to time constraints) was the existence of all those extra tear tag codes mentioned in another thread... we still only saw 4 codes (CRD0, CRD1, BMD0, FDH2) and their corresponding calibration part number. Also, I did not bring up the possibility of flashing the actual s/w (not just calibrations as is the case with chips and tuners), I'll discuss this at my next visit in a week's time.
So what all this seems to generate is a tree of revisions, some of which might actually be completely identical, ie:
FDH2 series might spawn 3 updated calibrations, BMD0 might have 1 additional new calibration (which could be identical to the 2nd update for FDH2), CRD1 might only have 1 existing calibration (that might be identical to the 3rd update for FDH2), etc.... all fictitious examples, but meant to illustrate how the existence of dozens of part numbers for calibrations doesn't mean there are dozens of unique calibrations.
After having this discussion, I can now see where it might be possible to have so many software revisions out there for Ford PCMs. A mention was made of 12000 in total... I think I can believe that, since looking at a model like our Marauder, just the fact of having 4 different 'packages' leave the ***embly line over the course of a model year means that even one update that is common to all 4 'packages' will generate 4 parts numbers.
Hope this makes sense. It was a long convoluted discussion involving pen and paper and lots of scribbling to try and make sense of this method of software configuration management. Please feel free to poke holes in all this, I'll deliver whatever remaining uncertainties we have to the technician next time we meet (within 2 weeks, for sure).
In case Terrebonne Ford's Eric Aumont is reading this, thanks for taking the time this morning to explain all this.