The on-board diagnostics, or OBD, code P0442 can often be fixed by tightening the gas cap or replacing the gas cap. The code indicates a small leak in the evaporative emissions, or EVAP, system, which is commonly caused by a loose gas cap or a small hole in the cap. Not all EVAP codes can be fixed by replacing the gas cap as there could be leaks in other parts of the car.Continue Reading
Further troubleshooting solutions include performing an EVAP test or using advanced diagnostic tools. These advanced solutions should typically be done by a professional mechanic.
The OBD system, known as OBD-II in most cars, runs on a vehicle's engine control unit (ECU). It continually runs diagnostic tests to detect malfunctions in the engine. If a problem is found, it stores a code that gives an indication of the issue, which can be read with an OBD-II scanner. While an OBD-II code can have several causes, it still narrows down the problem to a general area, such as the EVAP system or a particular component like a knock sensor.
Pulling the codes off an ECU is generally the first step of a diagnostic process. Once a repair is made, the codes can be reset. The check engine light will return if a new code is found because the problem was not completely fixed.Learn more about Car Parts & Maintenance
Common fixes that solve on-board diagnostic fault codes in a vehicle include replacing the oxygen sensor, tightening or replacing the gas cap, replacing the catalytic converter, replacing the mass airflow sensor and replacing one or more spark plugs or spark plug wires. Check your vehicle's on-board diagnostic system using an ODB II fault code scan tool, or bring the vehicle to an automotive repair specialist to discover the precise cause of the error.Full Answer >
A lit check engine light in a vehicle is indicative of one or more problems including faulty oxygen sensors, leaking hoses or manifolds, damaged fuel injector O-rings, a blown head gasket and a loose or damaged gas cap. A blinking check engine light indicates an emergency problem that requires repair.Full Answer >
Each state has different procedures for vehicle emissions testing, but common procedures include checking the fuel tank filler restrictor, ensuring that the gas cap seals tight, looking for the catalytic converter under the vehicle and looking at the instrument panel to see if the "Check Engine" light is illuminated. Most states use emissions testing to check for unburned hydrocarbons and carbon monoxide, and other states additionally check for carbon dioxide for diagnostic reasons.Full Answer >
A bad gas cap causes the “check engine” light to come on and does not hiss when unscrewed. It may also cause the car to smell like gas.Full Answer >