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

TesterPresent_Timer_State 
This status flag is set by any service which requires the tool to send 
TesterPresent 
($3E) 
messages 
to 
remain 
active. 
While 
TesterPresent_Timer_State = ACTIVE, the diagnostic application 
checks the TesterPresent_Timer. Mode $3E messages are used to 
reset this timer. If a Mode $3E message is not received every P3
C
ms, 
the timer expires and causes the device to exit Diagnostic Mode.
 
INACTIVE 
ACTIVE/INACTIVE 
normal_message_transmission_status 
This is a flag that is set in the $28 service when normal 
communications have been shut off and DTCs are disabled.
 
ENABLED 
ENABLED/DISABLED 
TesterPresent_Timer 
TesterPresent ($3E) service request messages are used to reset this 
timer. When active, if a TesterPresent ($3E) request message is not 
received within the P3
C
timing window, the timer expires and shall 
cause the node to execute the equivalent of a ReturnToNormalMode 
($20) service.
 
0 
$00 thru P3
Cmax
DTC_send_on_change_flag 
This flag is used to indicate that the send-on-change reporting of DTC 
count information is currently active. This flag is activated as soon as 
the tester requests service $A9 message $82 with a non-zero 
send-on-change status mask. It is then used by the steady-state DTC 
count reporting function to enable updated count information to be 
calculated and reported back to the tester (if a count change is 
detected).
 
$00 
$01 = send on change 
active 
$00 = send on change 
inactive 
programming_mode_active 
This flag is set in service $A5 and is used to keep track of whether or 
not a programming event has been enabled.
 
NO 
YES/NO