General Specification Electrical Function gmw3110 General Motors Local Area Network Enhanced Diagnostic Test Mode Specification

9.3.3 Product Memory (Operational Software and Calibration) File Requirements. 
Product memory files 
released to the assembly plant or service shall be in binary format. 
All files (e.g., software, calibration, utility file, drawing files, archives, etc.) distributed to GMNA assembly plants 
or GMNA service facilities shall meet all of the requirements specified in the GM World Wide Software and 
Calibration Parts Application Program Interface specification. In addition, all binary files (e.g., software, 
calibration, utility file) and their associated drawing files shall have the file base name the same as the part 
number released through the Product Description System (PDS). 
The Module ID for the Operational Software data file shall be $01. 
Note:
If the ECU has more than one microprocessor, then Module Id $01 shall be assigned to the operational 
software module of the processor that handles serial data for reprogramming. 
The ECU software and calibration files shall have a header as defined in paragraph 9.3.3.1. The header 
information is transferred to the appropriate ECU during the programming event. Portions of the header 
information are optionally programmed into the ECU permanent memory. 
9.3.3.1 Software and Calibration File Header Requirements (Table 219). 
Table 219: ECU Software and Calibration Module Header Definition 
Offset 
Number 
of Bytes 
Name 
Description 
Cvt 
$00 
2 
CS 
Module 
c
heck
s
um or CRC (hex) 
M 
$02 
2 
MID 
M
odule 
ID
(hex) 
M 
$04 
1 to 2 
HFI 
This field contains a 
H
eader 
F
ormat 
I
dentifier (HFI). The HFI 
is used to indicate the length of the Software Module 
Identifier (SWMI) field, the length of the Design Level Suffix 
field, and whether or not the Product Memory Address and 
Module Length fields are included in the header. Refer to