Diagnostic Service Identifier (SID) range and associated Diagnostic Protocols

In this article we will discuss the Diagnostic SID (Service Identifier) range, UDS services list and different Diagnostic Protocols (UDS, SAE J1979 OBD-II) associated with them.

What is a Diagnostic SID (Service Identifier)?

A Diagnostic SID (Service Identifier) is used in diagnostic protocols for a specific service or functions associated with vehicle ECUs. It is a numerical or alphanumeric code. An example of SID is Service Identifier $10 which is Diagnostic Session Control in UDS protocol.

Diagnostic SID range defines a category of SID values associated with any Diagnostic protocol.

SIDs, which are integral components of standardized diagnostic protocols like OBD-II (On-Board Diagnostics II) and UDS, plays a crucial role in vehicle diagnostics. They are utilized to request information from or send commands to ECUs.

Each SID corresponds to a diagnostic service, like reading sensor data, clearing DTCs, conducting system tests, or accessing ECU parameters.

Diagnostic tools or scanners use these SIDs to communicate with the ECUs and perform diagnostic tasks.

What is a vehicle Diagnostic Protocol?

A vehicle diagnostic protocol refers to a communication protocol used by vehicle ECUs to communicate with a diagnostic tool or scanner tool. These protocols enable engineers and technicians to diagnose any issues within the vehicle. These issues could be engine performance, transmission problems, ABS (Anti-lock Braking System) malfunctions, and more.

Unified Diagnostic Services (UDS) and SAE J1979 (OBD-II) are examples of vehicle diagnostic protocols.

Diagnostic Service Identifier (SID) range overview (0x00 – 0xFF)

Let’s discuss about the SID range and associated Diagnostic Services:

SID Range (hex)Service TypeStandard Name
$00 – $0FOBD Requests (SAE J1979 OBD-II)ISO 15031-5
$10 – $3EUDS RequestsISO 14229-1
$3FNot Applicable (N.A.)Reserved
$40 – $4FOBD ResponseISO 15031-5
$50 – $7EUDS ResponseISO 14229-1
$7FNegative ResponseISO 14229-1
$80ReservedISO 14229-1
$81 – $82ReservedISO 14230
$83 – $87UDS RequestsISO 14229-1
$88 – $9FRequestsReserved for Future definition
$A0 – $B9RequestsDefined by Vehicle Manufactures (OEM)
$BA – $BERequestsDefined by Suppliers
$C0ReservedISO 14229-1
$C1 – $C2ReservedISO 14230
$C3 – $C7Positive ResponseISO 14229-1
$C8 – $DFPositive ResponseReserved for Future definition
$E0 – $F9Positive ResponseDefined by Vehicle Manufacturers (OEM)
$FA – $FEPositive ResponseDefined by Suppliers
SID range and associated Diagnostic protocol


As seen above, the Diagnostic Service Identifier (SID) range defines Diagnostic requests and responses for UDS and OBD-II protocols. Some of the values reserve for future use. This list is useful to quickly identify the Diagnostic protocol involved based on the Diagnostic Service Identifier.

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