Interpreters Document

1A
C10100005A08FD09FF1B00000000FF 
S113000008
53
01010000000A000B000000000000FF 
9. For Single Wire GMLAN CAN, the pre utility file process as defined in GMW3110 handles the high 
voltage wake up message. 
10. If the VIN, Repair Shop Code, Programming Date or End Model Part Number are written to the ECU, it 
is recommended that this be done in part two of the utility file after programming and ECU reset.
Repair shop code and Programming Date should be stored in flash memory. 
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11. The utility file needs to comprehend how the ECU reacts to a request for a part number if the part is not 
fully programmed. For example, some ECU‟s when running out of boot will go to a fixed memory 
location and report out the contents of those memory locations as the part number. If the data file had 
been previously successfully programmed the reported data is correct. If programming was interrupted 
you may get bogus data (e.g. FF FF FF FF) or you may get a valid part number even though the 
complete data file had not been programmed. This can occur if the boot code retrieves the part 
number from the memory where the GMLAN header is written and programming had been interrupted 
after the header data was written to flash. There are several ways to get around this. One would be to 
have the boot check the validity of that particular data file and reject the part number request with reject 
code $31 if the data file was not fully programmed. The utility file could then be setup to jump to the 
appropriate line to reprogram the partially programmed data component. A second method to get 
around this is to use a combination of $A2 and $50 Op-Codes. The $A2 Op-Code will retrieve the 
programmed state of the ECU and dump it into one of the utility file buffers. The $50 Op-Code can 
then be used to verify that software is programmed before proceeding to the Op-Codes to check the 
software part numbers. If the software were not programmed then the utility file would jump directly to 
program op-software. If software is programmed then check the part numbers to see if the software 
needs to be updated (see above use of the $1A and $53 Op-Codes). If the software part numbers 
match then the utility file can jump to just program the calibration section. Note also that the use of the 
$50 Op-Code needs to comprehend whether or not the ECU supports any of the memory failure 
responses ($5x) that the ECU may send when checking to see if software is present. 
12. The utility files should be designed to compare part numbers of software components to determine if 
software and calibrations are to be programmed or just calibrations (see above descriptions on use of 
Op-Code $1A and Op-Code $53). It is not necessary (or desirable) to check individual calibration file 
part numbers in the utility file unless the ECU supports reprogramming of subsets of the calibration 
data files. If all calibration data files must be programmed as part of the same programming event it is 
not necessary to compare these part numbers. 
13. The module Id field in the $B0 Op-Code must match the module Id field in the drawing file for the data