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

7.3 Negative Response Message Flow Example. 
7.3.1 Tester Requests An Unsupported Service. 
In the following example (Table 41), a tester sends a 
physically addressed request to an ECU for a diagnostic service that is not supported. This results in the ECU 
sending a negative response with the returnCode set to $11 (ServiceNotSupported). 
The following information is given for the 
example:

The USDT request CANId for the ECU is $241 (and thus, the USDT response CANId is $641). 

The Diagnostic Service Requested is SecurityAccess ($27) and the ECU does not support this service. 
Table 41: Negative Response Message Flow Example 
– ServiceNotSupported 
T = Frame Sent By Tester, N = Frame Sent By Node; shaded region indicates PCI 
Frame Type 
CAN Id 
#1 
#2 
#3 
#4 
#5 
#6 
#7 
#8 
T(USDT-SF) 
$241 
$02 
$27 
$01 
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N(USDT-SF) 
$641 
$03 
$7F 
$27 
$11 
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8 Diagnostic Services (Test Modes) Definition 
Note:
This section describes the detailed operation of each individual test mode. 
8.1 ClearDiagnosticInformation ($04) Service. 
The ClearDiagnosticInformation service is used by the tester 
to clear diagnostic information in one or multiple nodes
’ memory. The ClearDiagnosticInformation service is 
based on the ClearDiagnosticInformation service specified in ISO 15031-5 (SAE J1979: test mode $04). 
8.1.1 Service Description. 
The node shall send a positive response upon receipt of a 
ClearDiagnosticInformation request (even if no DTCs are stored). It is understood that it may take the node 
additional time after the positive response to actually complete the clearing of all DTC information. If the 
amount of time to complete the clear DTC information exceeds 1 s, the worst case time must be documented 
in the Component Technical Specification. If a node supports multiple copies of DTC status information in 
memory (e.g., one copy in Random Access Memory (RAM) and one copy inElectronically Eraseable 
Programmable Read Only Memory (EEPROM)), the node shall clear the copy used by the DTC status 
reporting service ($A9) followed by the remaining copy. 
DTC information reset/cleared via this service includes but is not limited to the following: 

DTC status byte (see ReadDiagnosticInformation ($A9) service). 

Freeze frame data (emission related node(s) only). 

Failure record information. 

Other DTC related data such as flags, counters, timers, etc., specific to DTCs. 
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