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

Procedure 5: 
(If ECU implements this RC_).
 
1. Send a $3B message with a dataIdentifier and associated data bytes after the sub-parameter to the ECU 
when the ECU needs more than P2
C
ms to write data bytes to memory and verify the negative response 
($7F $3B $78 - RequestCorrectlyReceived-ResponsePending) within P2
C
ms and eventually a positive 
response message. 
Procedure 6: 
(If applicable).
 
1. If the ECU does any type of validity checks on the data being written, send a request with invalid data and 
verify the $7F $3B $31 negative response. 
Procedure 7:
(Only applicable if ECU has DIDs that require the usage of a security code). 
Note:
Security code as defined in the Vehicle Theft Deterrent SSTS 
1. Send a $3B message with a security code required dataIdentifier and associated data bytes after the 
dataIdentifier to a secured ECU (security code has not been entered) and verify the negative response 
($7F $3B $31 - RequestOutOfRange). 
2. Send a $3B message with a security code required dataIdentifier and associated data bytes after the 
dataIdentifier when the security code has been entered
 
and verify the positive response. 
3. Repeat steps 1 and 2 for each DID that requires the security code. 
8.14.8 Tester Implications. 
This service should be used with physical addressing.
 
 
CameraLoops.com

---

GM WORLDWIDE ENGINEERING STANDARDS 
GMW3110 
© Copyright 2010 General Motors All Rights Reserved 
February 2010 
Page 175 of 336 
8.15 TesterPresent ($3E) Service. 
This service is used to indicate to a node (or nodes) that a tester is still 
connected to the vehicle and that certain diagnostic services that have been previously activated are to remain 
active. Some diagnostic services require that a tester send a request for this service periodically in order to 
keep the functionality of the other service active. Documentation within this specification of each diagnostic 
service indicates if a given service requires the periodic TesterPresent request to remain active.