Introduction to UDS Simulator

The Next Generation UDS Simulator is a high-fidelity diagnostic simulation environment designed for automotive engineers, developers, and educators.

What is UDS Protocol?

Unified Diagnostic Services (UDS, ISO 14229) is an international diagnostic communication protocol used in ECUs (Electronic Control Units) within automotive electronics. It allows digital diagnostic tools to query fault codes, read live data, perform actuator tests, and flash new firmware.

Core Pillars

Service Identifier (SID): A 1-byte unsigned integer (0x00–0xFF) placed at byte position 0 of every UDS request. It uniquely identifies the diagnostic operation. The ECU echoes the SID in its positive response at byte 0, offset by +0x40 (e.g., request SID 0x22 yields positive response 0x62).
Client-Server Architecture: The Tester acts as the Client (Diagnostic Tool); the ECU acts as the Server.
Diagnostic Sessions: Different operational modes (Default, Extended, Programming) that enable specific services and timing parameters.
Negative Responses: Standardized error codes (NRCs) sent when a request cannot be fulfilled (e.g., security access denied, or incorrect message length).

ISO-TP Transport Layer

While UDS defines the application layer, it usually runs over ISO-TP (ISO 15765-2) when using CAN-bus. ISO-TP handles the fragmentation of messages larger than 8 bytes into multiple CAN frames (Flow Control, First Frames, and Consecutive Frames). The simulator abstracts this for simplicity, but respects the multi-frame response logic in the Terminal.

Simulator Features

ISO 14229 Compliant

Full support for 19+ standard UDS services including 0x10, 0x22, 0x27, 0x2E, 0x31 and more.

Precision Timing

Realistic simulation of P2 and P2* windows, including S3 server timeout handling.

Fault Injection

Test resilience with simulated failures like voltage drops, security breaches, and protocol violations.

Quick Start Guide

1. Power Up the ECU

Navigate to the Simulator page. By default, the ECU starts in the Default Diagnostic Session (0x01). Ensure the ignition indicator is green.

2. Send Your First Request

Select “Diagnostic Session Control (0x10)” from the Service Selector. Choose “Extended Session (0x03)” and click “Send Request”.

3. Observe the Bus

Watch the Terminal Output. You should see a TX frame (10 03) followed by a positive RX response (50 03 ...). The system status will update to “Extended Session”.

Tip: Next step: Try reading live vehicle speed by switching the service to ReadDataByIdentifier (0x22) and selecting the Vehicle Speed DID.

User Interface Guide

Your gateway to toggling modes and global settings. Access core functionality from any page.

Request Builder & Terminal

Compose hex frames using the Service Selector. The tool automatically adapts its input fields based on the selected UDS service.

Live Cluster Dashboard

A dynamic, photorealistic instrument cluster that responds to your UDS commands. It visualizes data read via SID 0x22 in real-time.

System Requirements

✓ Modern Web Browser (ES6+ Support)
✓ JavaScript Enabled
✓ Min Resolution: 1280x720 (Recommended)