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

8.18.5.2 Example #2 - Functional Read Status of DTC by Status Mask. 
In this example (Table 185), the 
tester requests all ECUs to report all DTCs that have a current or history status (status mask = $12). The 
request with $Level = $81 is followed by a single UUDT message from each ECU for each DTC that matches 
the masking criteria. Once all DTC information has been sent, each ECU will transmit an endOfDTCReport 
message to flag the completion of the transfer to the tester. 

Assume the TCM has no DTCs matching the masking criteria. As a result, only the endOfDTCReport 
message is sent. 

Assume the ECM has two DTCs matching the masking criteria: P0100 (DTCFailureTypeByte $00) and 
P1864 (DTCFailureTypeByte $00). 
Table 185: Example of Functional Request For ReadDiagnosticInformation with Sub-Parameter = $81 
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) 
$101 
$FE 
$03 
$A9 
$81 
$12 
--- 
--- 
--- 
N1(UUDT) 
$541 
$81 
$01 
$00 
$00 
$39 
--- 
--- 
--- 
N2(UUDT) 
$543 
$81 
$00 
$00 
$00 
$FF 
--- 
--- 
--- 
N1(UUDT) 
$541 
$81 
$18 
$64 
$00 
$07 
--- 
--- 
--- 
N1(UUDT) 
$541 
$81 
$00 
$00 
$00 
$FF 
--- 
--- 
--- 
Note:
Tester should wait for all ECU(s) to return the endOfDTCReport message before transmitting another 
$A9 $Level $81 request message. 
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