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

GM WORLDWIDE ENGINEERING STANDARDS 
GMW3110 
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February 2010 
Page 209 of 336 
ENDIF 
ENDIF 
ENDFUNCTION 
8.18.7 Node Verification Procedure. 
Procedure 1: 
1. Send a request for level $80 (if supported) with less than 3 data bytes after the sub-function parameter in 
the message. Verify the proper negative response ($7F $A9 $12). 
2. Send a request for level $80 (if supported) with more than 3 data bytes after the sub-function parameter in 
the message. Verify the proper negative response ($7F $A9 $12). 
3. Send a request for level $81 with no data bytes after the sub-function parameter. Verify the proper 
negative response ($7F $A9 $12). 
4. Send a request for level $81 with more than 1 data byte after the sub-function parameter. Verify the proper 
negative response ($7F $A9 $12). 
5. Send a request for level $82 (if supported) with no data bytes after the sub-function parameter. Verify the 
proper negative response ($7F $A9 $12). 
6. Send a request for level $82 (if supported) with more than 1 data byte after the sub-function parameter. 
Verify the proper negative response ($7F $A9 $12). 
7. Send a request for each optional sub-function parameter not supported by the ECU ($80 or $82). Verify 
the proper negative response ($7F $A9 $12). 
8. Send a request with a sub-function parameter value which is not supported by this service. Verify the 
proper negative response ($7F $A9 $12). 
9. Send a request for this service (with any valid sub-function parameter) at a time when the ECU cannot 
send a response within P2
C
. Verify that the ($7F $A9 $78) response is sent followed by the proper positive 
response within the time values specified in the Negative Response ($7F) Service Definition section of this 
specification. 
Procedure 2: 
(Verification Of The readStatusOfDTCByStatusMask $81 Level.)
 
1. Send a ClearDiagnosticInformation ($04) request. Then send a request for service $A9 with the sub-
function parameter equal to $81 and the current bit set in the status mask. Verify that only the $81 UUDT 
endOfDTCReport positive response is sent, and that no additional UUDT messages follow. For the 
endOfDTCReport message, verify that the DTC/failure type byte combination is set to $00 00 (i.e., $00 $00 
$00), and verify that supported bits in the status availability mask are correct for the ECU. 
2. Set a DTC (this can be done by disconnecting a sensor input that is known to cause a single DTC to 
immediately become current). Then send a request for this service with the sub-function parameter equal 
to $81 and the current bit set in the status mask. Verify that the DTC information is correctly reported in the 
UUDT response message, followed by an appropriate endOfDTCReport message. 
3. After completing step 2 above, send a request for this service with the sub-function parameter equal to 
$81. In the request message, define a status mask with the current bit set, and an unsupported status bit 
also set. Verify that the responses are identical to those from procedure 2. 
4. Using instrumentation or other means available to view the status of DTCs, manipulate ECU inputs and 
outputs to cause DTCs to set each of the status bits supported by the ECU. Send requests for this service 
with the sub-parameter set to $81 and a status mask of $FF, and verify each time that the correct DTC 
Numbers, FaultTypes, and Status information are returned in the UUDT response messages. In each 
case, verify that an appropriate endOfDTCReport message is sent, and that no further UUDT responses 
follow.