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

GM WORLDWIDE ENGINEERING STANDARDS 
GMW3110 
© Copyright 2010 General Motors All Rights Reserved 
February 2010 
Page 161 of 336 
8. Perform security sequence. Send a DisableNormalCommunication request message, verify positive 
response. Begin TesterPresent message periodic. Enable programming mode with the $A5 service. Send 
RequestDownload message with a valid dataFormatIdentifier and an invalid unCompressedMemorySize 
parameter value. Verify proper negative response reject message ($7F $34 $12, sub-function not 
supported) is sent. 
9. With the manufacturers enable counter > $00 or vulnerability flag = $FF and security has not been 
accessed (SecurityAccess ($27) request has not been sent),
 
send a DisableNormalCommunication 
request message, verify positive response. Begin TesterPresent message periodic. Enable programming 
mode with the $A5 service. Send RequestDownload message with a valid dataFormatIdentifier and 
unCompressedMemorySize parameter value. Verify that negative response message ($7F $34 $22, 
conditions not correct) is sent (because security has not been accessed). 
10. With the manufacturers enable counter > $00 or vulnerability flag = $FF, perform security sequence. Send 
a DisableNormalCommunication request message, verify positive response. Begin TesterPresent 
message periodic. Enable programming mode with the $A5 service. Send RequestDownload message 
with a valid dataFormatIdentifier and unCompressedMemorySize parameter value. Verify positive 
response message. 
Procedure 3: 
(If negative response code $78 is supported by the ECU). 
1. Perform security sequence. Send a DisableNormalCommunication request message, verify positive 
response. Begin TesterPresent message periodic. Enable programming mode with the $A5 service. 
Create the conditions under which the ECU should return a $7F $34 $78 response and send a valid 
request for this service. Verify that proper response is sent. 
2. Repeat previous step of this procedure for each possible reason an ECU would send the negative 
response with response code $78.