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

C
and P2
C
* within this specification are references to the ECU timing parameters P2
CE
and P2
CE
* unless otherwise noted (e.g., P2
CT
or P2
CT
*). 
6.2.1.1 ECU Timing Parameter P2
CE 
(Table 27). 
The timing parameter P2
CE
is defined to be the time between 
the end of the tester request message and the completion of either a single frame response, the first frame of a 
multi-frame response message, or the first UUDT message transmitted by the ECU in response to a service 
$AA or $A9. 
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GM WORLDWIDE ENGINEERING STANDARDS 
GMW3110 
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February 2010 
Page 50 of 336 
Table 27: P2
CE
 Timing Parameter Value 
Parameter 
Description 
Minimum 
(CEmin) 
 [ms] 
Maximum 
(CEmax) 
[ms] 
P2
CE
Time between tester request (N_USData.ind) and the ECU 
response as follows: The ECU has to make sure that a USDT single 
frame response message, the first frame of a multi-frame response 
message, or the first UUDT response message is completed 
(successfully transmitted onto the CAN bus) within P2
CE
0 
100
Note 1
Note 1:
OBD/EOBD devices are required to support the timing value P2
CE
as specified in ISO 15031-5 (referred to as P2
CAN
in 
ISO 15031-5) for emission related services. An OBD/EOBD device may choose to use a single value for P2
CE
for both emission related 
and enhanced diagnostic services provided that the value used is not greater than the value specified in this table. 
The request message sent by the tester can either be a single frame (with address type either functional or 
physical), or a multi-frame message (with address type physical only). The end of a tester request message is 
indicated to the application layer in the ECU by the network layer (N_USData.ind). 
Note:
The network layer of a message sender only indicates the completion of an entire message (single 
frame/multi-frame USDT message, or UUDT message - see Figures 16 thru 18) to the application layer 
(N_USData.con, N_UUData.con). The network layer does not indicate the completion of the transmission of 
only the first frame of a multi-frame message.