Send ISO 14229 diagnostic requests to a virtual ECU and inspect every response byte, in your browser, with no hardware.
The simulator pairs an interactive request console with a virtual ECU that implements all 19 core UDS services. Compose a request as raw hex or through the guided service builder, send it, and watch the response decode field by field: service identifier, sub-function, data identifiers, and payload. Negative responses are returned with the negative response code ISO 14229 actually specifies for that condition, not a generic failure.
DiagnosticSessionControl (0x10), ECUReset (0x11), ClearDiagnosticInformation (0x14), ReadDTCInformation (0x19), ReadDataByIdentifier (0x22), ReadMemoryByAddress (0x23), SecurityAccess (0x27), CommunicationControl (0x28), ReadDataByPeriodicIdentifier (0x2A), WriteDataByIdentifier (0x2E), RoutineControl (0x31), RequestDownload (0x34), RequestUpload (0x35), TransferData (0x36), RequestTransferExit (0x37), WriteMemoryByAddress (0x3D), TesterPresent (0x3E), AccessTimingParameter (0x83) and ControlDTCSetting (0x85).
The virtual ECU tracks the active diagnostic session, the security access level, and the S3 session timeout, exactly as a real server would. Requesting a service that the current session does not permit returns NRC 0x7F; requesting one that needs an unlocked security level returns NRC 0x33. Sending TesterPresent (0x3E) resets the S3 timer and keeps a non-default session alive.