Gathering evidence for a car warranty claim should start from the actual conditions of use. Confirm the photos, videos and repair work orders first, then verify the VIN, mileage and time of failure and the diagnostic codes and test records. When the fault occurs, freeze the software version and vehicle state first, then keep the VIN, mileage, fault codes, photos and repair work order, so the evidence doesn't disappear after disassembly and repair. The records must trace back to the VIN, mileage and time of failure and the diagnostic codes and test records; when the photos, videos or repair work orders change, revise the documents first, then decide whether to proceed. When finished, have the person responsible for car warranty claim documents sign off, record the date of the documents used, and note any exceptions that must be cleared before the next step.
While preparing the documents, open What inspection records should buyers keep for each exported Chinese car?. The supply and warranty responsibility for car warranty claim documents must be written into the contract or service agreement; a supplier's verbal assurances are no substitute for a long-term commitment.