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GUIDE / OBD-II

待定码、确认码与永久码

待定码可能表示初次监测失败；确认码则满足模块的确认条件。支持永久排放故障码的车辆通常需要相关监测确认修复后自行清除，不能仅靠扫描仪清码。条件因车辆和地区而异。存储有码不等于故障现在仍存在。

更换零件之前

记录报码及冻结帧，检查蓄电池状态、相关报码和可见的线束或软管损伤。按照该车诊断流程和测试结果决定维修，避免仅凭故障码换件。

扫描记录表 →

有原厂依据的故障码释义

P0300随机或多缸失火P0420催化系统效率低于阈值 · 气缸列 1P0171混合气过稀 · 气缸列 1P0299涡轮／机械增压器 A 增压不足

来源与解读范围

先理解含义，再核对所引原厂页码。通用参考说明和限定车型案例的适用范围不同，采用维修指令前须确认具体应用。

  1. 2017 MY OBD System Operation Summary for Diesel Engines — revision July 29, 2016 ↗

    Ford Motor Company · PDF 201, 202

    Ford 2017 diesel diagnostic-executive example: pending, confirmed and permanent DTC setting/erasure, including monitor-dependent exceptions. Page 202 also documents EWMA confirmation behavior. Applies to engines and programs covered by this manual, not every OBD-II vehicle; avoid a universal two-trip rule.

  2. On-Board Diagnostic Test Reference — Section C, Permanent diagnostic trouble code standards ↗

    California Bureau of Automotive Repair

    California Smog Check reference: supported permanent DTCs survive scan-tool clearing and battery disconnection and are removed by the OBD system after verification. Model-year support and inspection exceptions are California-specific; this guide does not prescribe those local pass/fail limits.