User´s Manual - I+ME ACTIA GmbH

Read Data by Packet Identifier
The purpose of the Read Data By Packet Identifier ($AA) service is to allow a tester to request data
packets that contain diagnostic information (e.g. sensor input or output values) which are packaged in a
UUDT diagnostic message format. Each diagnostic data packet includes one byte that contains a Data
Packet Identifier (DPID) number, and 1 to 7 bytes of additional data. The DPID number occupies the
message number byte position of the UUDT diagnostic response message and is used to determine the
data contents of the remaining bytes of the message.
Note: This service is intended to be used to retrieve ECU data, which is most likely changing during
normal operation (e.g. ECU sensor inputs, ECU commanded output states, etc). Static information such
as VIN or Part Numbers should be retrieved via the Read Data By Identifier ($1A) service.
The DPIDs requested via this service can be sent as a one-time response or scheduled periodically. Each
DPID scheduled can be transmitted at one of three predefined periodic rates (slow, medium or fast).
The Read Data By Packet Identifier service request message includes a sub-function parameter and at
least one DPID number when the request is for a one time response (sub-function parameter $01) or
periodic transmission (sub-function parameters $02 through $04). A single request to stop sending one
or multiple periodic DPIDs (sub-function parameter $00) may be sent with or without additional DPID
data.
Depending on the required action the service has to be configured. Therefore the Setup button in the
Main Diagnostic Setup window could activate the dialog box shown below.
Sub Function Parameter
Stop Sending $00
Stops periodic transmission of the DPIDs that have been chosen to be requested.
Send One Response $01
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