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

Procedure 3: 
(If negative response code $78 is supported by the ECU.)
 
1. Disable normal communication and verify the positive response. Send TesterPresent requests as 
necessary to keep normal communications disabled. 
2. Create conditions under which the ECU should return the $7F $A5 $78 response to a request for this 
service. Send a valid request for this service and verify the $7F $A5 $78 response followed by a final 
response within the P2
C
* timing window. 
3. Repeat steps 1 and 2 of this procedure for each possible reason an ECU would send the negative 
response with response code $78. Verify this for each applicable supported sub-function parameter. 
8.17.7 2 Additional Verification Procedures for Nodes on Mid-Speed or High Speed Busses. 
Procedure 1: 
1. Disable normal communication, send a requestProgrammingMode_HighSpeed message ($A5 $02), and 
verify that the ECU sends a negative response ($7F $A5 $12). 
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GMW3110 
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8.17.7.3 Additional Verification Procedures for Switch To High Speed Programming Mode. 
(SWCAN 
only) 
Procedure 1: 
(Perform this procedure when conditions would allow a programming event.)
 
1. Disable normal communication, send a requestProgrammingMode_HighSpeed message ($A5 $02). 
Verify the positive response ($E5) message. 
2. Send an enableProgrammingMode request ($A5 $03). Verify no response is sent. 
3. Wait at least 30ms (but less than 50 ms), then send a request for a supported mode (e.g., Mode $34 
RequestDownload). Verify the proper high speed response. 
4. Keep the device in enableProgrammingMode for at least 2 minutes by sending TesterPresent (mode $3E) 
messages at an interval less than P3
C
ms. Verify that no normal communication messages are 
transmitted. 
5. Verify that the device communicates in high speed Programming Mode by periodically sending valid 
request messages. 
6. If the device is programmable, verify that the device is capable of being programmed using a released 
utility file for high speed programming and the correct interpreter software. 
7. Repeat steps 1 thru 4 of this procedure and then send a ReturnToNormalMode ($20) message. Verify 
that the ECU switches the protocol converter back to low speed operation and then performs a software 
reset. Wait 1 s and then send a request for a supported diagnostic service at low speed. Verify the proper 
response. 
8. Repeat the above procedure except end the programming event by allowing a P3
C
(TesterPresent) 
timeout to occur (instead of sending a mode $20 request). Verify that the ECU switches the protocol 
converter back to low speed operation and performs a software reset. Wait 1 s and then send a request 
for a supported diagnostic service at low speed. Verify the proper response.