UDS Diagnostic Architecture: DEM, DCM, NM, and KopherUDS
UDS is the core diagnostic communication protocol for automotive ECUs. This article explains DEM event management, DCM diagnostic communication, NM network management, and KopherUDS use cases.
Quick Facts
Summary
Unified Diagnostic Services (UDS, ISO 14229) is widely used for ECU diagnostics, data readout, DTC management, routine control, and reprogramming. It can operate over CAN, CAN FD, or Ethernet transport.
In implementation, UDS is usually designed together with event management, communication management, network management, data identifiers, and security access.
DEM, DCM, and NM Responsibilities
| Module | Main Function |
|---|---|
| DEM | Fault events, DTC status, snapshot data, and aging logic |
| DCM | Diagnostic services, sessions, security access, DID, and routines |
| NM | Network wake-up, sleep, node state, and communication availability |
| Transport | CAN TP, DoIP, or other diagnostic transport handling |
Common UDS Services
| Service | Purpose |
|---|---|
| 0x10 Diagnostic Session Control | Switch default, extended, or programming session |
| 0x22 Read Data By Identifier | Read version, state, and measurement data |
| 0x19 Read DTC Information | Read DTC and event status |
| 0x27 Security Access | Protect privileged services |
| 0x31 Routine Control | Execute test, calibration, or production routines |
| 0x34 / 0x36 / 0x37 | Firmware download and transfer workflow |
KopherUDS Positioning
KopherUDS is a diagnostic communication stack for automotive ECUs. It can configure diagnostic services, DID, DTC, routine control, security access, and reprogramming flows while keeping engineering flexibility.
FAQ
Is UDS only for after-sales service?
No. UDS is also used during development, production EOL, diagnostics, data readout, DTC analysis, and ECU reprogramming.
Should DEM and DCM be designed together?
Yes. DTC reading, event status, and diagnostic services are tightly related and should be defined in a common diagnostic specification.
Can KopherUDS work with KITE UDS Tester?
Yes. KopherUDS provides ECU-side diagnostic capability, while KITE UDS Tester verifies responses, DID, DTC, reprogramming, and production test flows.
Technical sources and scope
These primary sources cover standards, components and communication principles. KopherBit features, ratings and deliverables remain company specifications subject to the selected model, revision and project validation. Citing a standard does not establish product certification.
- AUTOSAR R24-11 — Diagnostic Event Manager
DEM event and DTC management interfaces.
- AUTOSAR R24-11 — Diagnostic Communication Manager
DCM diagnostic service processing and UDS interfaces.
- AUTOSAR Classic Platform
Classic layered architecture and specifications.
Sources checked: 2026-10-03
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