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

ReportProgrammedState ($A2)
with 
the AllNodes CANId and AllNodes extended address (finalization of the diagnostic configuration 
matrix - on each link as needed). 

Each SPS programmable ECU shall respond. 

SPS_TYPE_A and SPS_TYPE_B ECUs respond with their permanent diagnostic USDT 
response CANId (which falls within the reserved range of diagnostic response CAN Identifiers). 

An SPS_TYPE_C ECU responds with the SPS_PrimeRsp CANId ($3xx where xx = diagnostic 
address). 

At this point the SPS_TYPE_C ECU would activate and accept the SPS_PrimeReq ($0xx) 
CANId as a diagnostic PTP request CANId (where xx = diagnostic address). 

MSSC ECUs shall only respond to the $A2 service on the subnet where they support 
programming (MSSC ECUs shall only be programmable on one subnet 
– see 4.3.4. 
7 
Retrieve necessary ECU ID and vehicle option content (e.g., engine type) information from the 
programmable node(s) (using 
ReadDataByIdentifier ($1A)
service). 

Use the SPS_PrimeReq ($0xx) diagnostic request CANId for each SPS_TYPE_C ECU targeted. 

Use USDT permanent diagnostic request CANId (determined based on offset from response 
CANId received) for SPS_TYPE_A and SPS_TYPE_B ECUs. 

Use information received via the previously executed service ReportProgrammedState ($A2) to 
identify all SPS programmable ECUs. 
8 
Retrieve seed of programmable module(s) using the 
SecurityAccess ($27)
service. 

Security may not be implemented in all ECUs that are SPS programmable. The SecurityAccess 
service is required for all SPS programmable ECUs that are Emission, Safety, or Theft related. 
9 
optional 
step 
Send a 
ReturnToNormalMode ($20)
request (with AllNodes CANId and AllNodes extended 
address - on each link as needed).

This request transitions all subnets back to normal operation while the tool is retrieving 
information from the SPS database. This step is optional since a P3
C
timeout would occur after 
the tester is disconnected and this shall also cause all nodes on all subnets to revert back to 
normal operation. 
10 
Disconnect tester. 
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