CAN 통신 위에서 동작하는 통합 진단 서비스
CAN에서 data가 UDS 메시지가 된다.
<구조>

PCI | SID | DID
목록: https://en.wikipedia.org/wiki/Unified_Diagnostic_Services

| Service ID (hex) | Service |
|---|---|
| 0x10 | Diagnostic Session Control |
| 0x11 | ECU Reset |
| 0x14 | Clear Diagnostic Information |
| 0x19 | Read DTC Information |
| 0x22 | Read Data By Identifier |
| 0x23 | Read Memory By Address |
| 0x27 | Security Access |
| 0x28 | Communication Control |
| 0x2A | Read Data by Periodic ID |
| 0x2E | Write Data By Identifier |
| 0x2F | Input Output Control By Identifier |
| 0x31 | Routine Control |
| 0x34 | Request Download |
| 0x35 | Request Upload |
| 0x36 | Transfer Data |
| 0x37 | Transfer Exit |
| 0x3D | Write Memory By Address |
| 0x3E | Tester Present |
| 0x85 | Control DTC Setting |
<긍정응답>
ECU가 SID+0x40값으로 응답.
<부정응답>
0x7f라는 error id와 sid, nrc를 반환
7f | SID | NRC
여기서 nrc는 negative response code로 각 값별로 의미가 다름