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

TesterPresent ($3E)
periodic messages to all nodes - all links as needed (using the 
AllNodes CANId and AllNodes extended address). 
29 
The tester must now issue a request for service 
ReadDataByIdentifier ($1A)
with 
DID $B0
in order to 
perform a relearn of the diagnostic address and CANIds. This is necessary because an ECU which 
was programmed and performed a reset after the ReturnToNormalMode ($20) service from Step 23, 
would now use its permanent CAN Identifiers. This step is performed automatically prior to the 
execution of utility file driven diagnostic service (e.g., Step 25) following the ReturnToNormalMode 
($20) service. 
30 
The 
WriteDataByIdentifier ($3B)
service may be used to program option content information into 
SPS programmable ECUs which were just programmed. 
 
Note:
The tester may send a service $04 request to clear DTCs at the conclusion of the programming event. 
This is typically done at the conclusion of module programming in the vehicle assembly plant. 
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GMW3110 
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February 2010 
Page 280 of 336 
9.4.4 Summary. 
Figure 40 contains the graphical representation of the GMLAN Programming Procedure as 
defined in the previous sections. 
Figure 40: Programming Procedure 
– Summary 
Note:
The Programming Procedure Summary shows the general steps of the GMLAN programming 
procedure. Optional steps are indicated with (Opt). 
9.5 ECU Programming Message Flow Example.
The following example assumes:
 

Programming is to be performed on a single node on the SWCAN low speed link. 

There are four nodes on the SWCAN link. 

Node 1 (N1) is an SPS_TYPE_A ECU that has a diagnostic USDT response CANId of $641, and a 
diagnostic address of $28. 

Node 2 (N2) is not programmable, has a diagnostic USDT response CANId of $64D, and a diagnostic 
address of $60. 

Node 3 (N3) is an SPS_TYPE_C ECU without operational software or calibration data and a 
diagnostic address of $40, (so its SPS_PrimeReq and SPS_PrimeRsp programming request and 
response CAN Identifiers are $040 and $340 respectively). Once Node 3 is programmed, its physical 
diagnostic request and response CANIds are $247 and $647 respectively. 

Node 4 (N4) is a Gateway ECU that is not programmable, has a diagnostic USDT response CANId of 
$651, and a diagnostic address of $42. 

Only the low speed subnet (SWCAN link) high voltage wake-up method is shown in the following 
examples. The High Voltage wake-up message for the SWCAN low speed link uses CANId $100. 

Node 3 (N3) is the only node which will be programmed during the programming event. 

For this example, it is assumed the ECU being programmed supports 4-byte addressing (uses address 
$00 $00 $23 $FF) and also is expecting a 4-byte uncompressed memory size with the $34 service. 
Utility File Process
Wake-Up Link(s) 
Start TesterPresent 
Determine GMLAN 
Communication 
Parameters 
Disable Setting 
DTCs (Opt.) 
Finalize the GMLAN 
Communication 
Parameters 
Retrieve ECU 
Identification 
Return to Normal 
Mode (Opt) 
Retrieve SPS Data 
out of the SPS 
Database 
Reconnect the 
Tester 
Retrieve Seed(s) 
Wake-Up Link(s) 
Start TesterPresent
Determine GMLAN 
Communication 
Parameters 
Disable Setting 
DTCs (Opt.) 
Finalize the GMLAN 
Communication 
Parameter 
Verify the Vehicle 
(Opt) 
Request for 
Programming 
Enable 
Programming 
Perform Security 
Access 
RequestDownload 
TransferData 
RequestDownload 
TransferData 
RequestDownload 
TransferData 
Return To Normal 
Mode 
Optional Steps 
Required to be 
Performed After the 
SW-Reset 
Start
End
RequestInfo Process
Pre-Utility File Process
(Multiple Interpreters Running in Parallel)