Toyota Sienna gas tank fills incompletely, stopping 3 to 4 gallons short due to design issue on Toyota Sienna

Some Toyota Sienna owners report experiencing issues with incomplete gas tank fills, where the tank stops filling 3 to 4 gallons short. These problems may stem from several potential causes, including malfunctions in the evaporative emissions control system, such as a faulty fuel tank inlet check valve or a clogged charcoal canister. Additionally, a damaged gas cap seal can prevent proper filling, making it essential to inspect for cracks or damage. Blockages in the vapor relief hose can also hinder the filling process by allowing vapor to escape up the filler hose. In some cases, issues with the fuel pickup tube may lead to inaccurate fuel readings and incomplete tank emptying. Furthermore, problems with the Onboard Refueling Vapor Recovery (ORVR) system can result in slow or incomplete fuel fills. To resolve these issues, owners are advised to inspect the relevant components and consult a qualified mechanic or dealership if the problem persists.