The focus of a pre-purchase vehicle inspection is to gather factual information on the vehicle’s current condition.
Typically, the evaluator is a mobile inspector who inspects the vehicle at its sale point. A short road test is usually included. Inspections are performed with the permission of the seller. The buyer can be present or not present during the inspection.
The inspected areas include structural integrity, safety features, electrical and electronic systems, powertrain, suspension, fuel system, emissions, steering, comfort system (heat/air), security system, exhaust, interior, wheels and rims, and apparent state of general maintenance. Hidden damage from crashes, flood, or rough use are checked.
Important for newer vehicles is an inspection of the onboard computer system, including recently cleared computer codes. The inspector also investigates for vehicle identification alteration, lack of recent license plates, salvage title, and odometer fraud.
Commercial vehicle inspections also evaluate the condition of items relevant to commercial use, such as conspicuity materials, markings and placards, insurance, service limits, coupling devices, etc.
Description from https://en.wikipedia.org/wiki/Pre-purchase_inspection
