OBD-II on Chinese cars: Chery, Geely, BYD, Great Wall — diagnostic specifics

Chinese cars (Chery, Geely, Great Wall, BYD, MG, Changan, Dongfeng) — fast-growing segment since 2020, especially in EU and Eastern Europe. But OBD-II diagnostics have specifics. Below: what works and how.

Standard: SAE J1979 + GB/T 27840

Chinese cars post-2010 must support SAE J1979 (base OBD-II) plus Chinese standard GB/T 27840 (extended). So:

• Standard OBD-II PIDs (Mode 01, 03, 09) — 100% supported across models
• DTC — standard P-, B-, C-, U- codes
• VIN — Mode 09 (see VIN decoder post)

GB specifics:

• Extra PIDs for EVs (BYD, Nio, XPeng)
• Extended EVAP for China market (lambda spec PN6-a)
• OBD-II connector may be under the seat (SUV Chery Tiggo) or under glovebox — standard location

Chery (Tiggo 7, Tiggo 8, Arrizo)

• Engine: TGDI 1.5L, 1.6L — in-house + FEV (Germany)
• OBD-II via ELM327: 100% for standard PIDs
• Manufacturer PIDs (via Mode 22): limited support, but Chery-specific PIDs exist for DPF (Tiggo 8 Pro Max), turbo boost, VVT

Note: Chinese Bosch ECU — same codes as Bosch VW/BMW but with different injector IMA (see injector coding post).

Geely (Coolray/Binyue, Atlas, Emgrand)

• Engine: 1.5T + 1.5T MHEV (Volvo-shared, Swedish OEM)
• OBD-II: full support + Volvo-like extensions
• AT diagnostics: Aisin AT with Volvo protocol (not generic Aisin)

Specific: Coolray on VOP2 platform supports BLE adapters. Factory software — Geely EDS 2 ($150 on Chinese store).

BYD (Tang, Han, Song Plus, Atto 3)

• Hybrid / EV: DM-i, EV, PHEV
• OBD-II: basic standard PIDs available, but BYD uses its own closed CAN protocol for BMS (battery management) — separate from OBD-II
• For BMS + charging — BYD-specific adapter (Zhichi diagnostic tool)

What ELM327 can do:

• P-codes for ICE (for DM-i / DM-p)
• VIN
• Speed, battery SoC (basic level)

What NOT:

• Battery health per cell (needs BYD tool)
• Motor inverter deep-level parameters

Great Wall / Haval (H6, H9, Jolion)

• Engine: 1.5T + 2.0T + PHEV
• OBD-II: full support
• Factory software: Great Wall SDS ($200)

Note: Haval has its own DTC set for body (B-codes) — doesn’t match Bosch/Continental. ELM327 may not decode description, only the code itself.

MG (Motor) — under SAIC

• MG ZS EV, MG 4 EV, MG Marvel R — EV
• OBD-II: standard PIDs + BMS via SAIC-specific
• Rover-like heritage (SAIC bought MG in 2005) — some DTCs like old Rover

Changan, Dongfeng, JAC — for our markets only

These brands have cars on their own platforms with in-house ECU. OBD-II via ELM327 works only for basic PIDs. Deep-level PIDs often unavailable. For service — need OEM tool from dealer.

General tips

• Get ELM327 with CAN-FD support — newer Chinese (BYD 2024+) use CAN-FD (see CAN-FD post)
• Not every OBD-II cable adapter fits — Chinese sometimes have shifted pins (verify pin 6/14 CAN High/Low)
• For EV BYD/Nio/XPeng — standard OBD-II gives only VIN + DTC; full diagnostics need brand-specific tool
• Language support: many Chinese codes have Chinese or broken English descriptions; our DTC Analyzer AI agent gives clean UK/EN translation

What Car Diagnostics does

We support standard OBD-II + experimental Chery / Geely / Great Wall / MG via Mode 22. BYD BMS — not supported, needs their BMS-scanner. See compatibility.

Try on free tier — pair an ELM327 adapter. Standard DTC on every Chinese car. Manufacturer PIDs for Chery/Geely — on paid tier.