The fuel tank pressure sensor measures the positive and negative pressure in the fuel tank. This sensor also monitors the vapors in the engine.The information gathered is sent to the engine control computer. If there is an issue, then the automobile's check engine light comes on.
The fuel tank pressure sensor is used to detect leaks as part of the EVAP, or Evaporative Emissions, system. The EVAP system was developed due to the environmental regulations that began in the 1970's. The chemicals in gasoline can kill if inhaled in large amounts and are the leading cause in air pollution. This system is used to send the vapors to the engine instead of into the atmosphere. The gas is evaporated in the gas tank. Once this happens, the vapors are stored in a charcoal canister. A valve then vacuums the mixture to the engine. The vapors are mixed with fresh air for better combustion and are released while the automobile is in motion. The system uses the fuel tank pressure system to detect if there are leaks in the system, which sets off the check engine light. This light is necessary to ensure that the EVAP system is properly working and complying with federal regulations. .