UDS DTC & ISO-TP Frame Tool
Convert UDS DTCs like P0420 to/from two-byte frames, build and parse ISO-TP single/first frames locally.
Sample input is pre-filled and editable. Everything runs locally in your browser — nothing is uploaded.
P/C/B/U use the top 2 bits; digits 2–3 encode the subsystem, low byte the fault id.
FAQ
The top two bits of the high byte encode P/C/B/U, the next two the subsystem, and the remaining 12 bits the fault id — hence P0420 → 04 20.
A classic 8-byte CAN frame spends one byte on PCI, leaving 7 data bytes. Longer payloads need a first frame plus consecutive frames.
How to use
The article body below is currently available in full only in Chinese; the interface, titles, descriptions and FAQ follow your selected language.
- DTC 编解码：输入
P0420得到报文字节；或输入04 20反解出故障码及分组、子系统字段。 - ISO-TP 帧：输入诊断载荷（≤7 字节）生成单帧；工具同时给出总长 120 字节的首帧示例，并对输入的 8 字节帧做 PCI 类型解析。
帧类型速查
| 首字节高 4 位 | 类型 | 说明 |
|---|---|---|
| 0x0 | 单帧 SF | 低 4 位 = 数据长度，≤7 |
| 0x1 | 首帧 FF | 低 4 位 + 第 2 字节 = 12 位总长度 |
| 0x2 | 连续帧 CF | 低 4 位为序列号 |
| 0x3 | 流控帧 FC | 块大小 / 最小间隔 |
常见诊断请求
22 F1 90（ReadDataByIdentifier）在本工具默认载荷里，可直接生成03 22 F1 90 AA AA AA AA。填充值 0xAA 是本工具采用的常见约定，并非标准强制；实际项目请按 OEM 诊断规范选择填充字节。
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