It's extremely difficult. Unauthorized modifications can lead to module current overload protection, resulting in a lock. In China, you need to use the factory online engineer account to reprogram it. It's basically impossible to perform online decoding overseas. We strongly warn against blindly modifying the electrical systems of modern integrated circuit vehicles.

A solid contract is your main protection in a cross-border deal. It should specify: 1. Vehicle identification: VIN, year, mileage, trim level, and photos of the actual car appended as an annex — not just「a 2021 Toyota」. 2. Condition guarantees: no accident, no flood or fire damage, no structural repairs, supported by a third-party inspection report referenced in the contract. 3. Price and Incoterm: total amount, currency, the named port, and whether freight and insurance are included. 4. Payment schedule: e.g., 20–30% deposit after contract signing, balance against copy of the Bill of Lading. Avoid 100% upfront. Use T/T to the company's corporate bank account only — never a personal account. 5. Timeline: inspection date, estimated loading date, and latest shipment date, with remedies if delayed. 6. Dispute clause: governing law and arbitration (CIETAC or your local chamber) rather than foreign court litigation. Ask for the contract in English (or bilingual) with the supplier's company chop. A company that refuses a written contract or pushes for full prepayment is a red flag.

Mainstream Chinese automakers rarely publish official English versions of their underlying circuit diagrams. We can provide some models' original Chinese technical documents (PDF) for B2B clients, which you will need to translate for your local mechanics using translation software.