had to replace the engine in my jeep with a jasper engine. the check engine light came on yesterday, mechanic said it was for the gas cap not being tight. is there even a sensor for the gas cap on a '99?
Just happened to me and the code is P1486. Which states the EVAP hose in a pinched condition. Contacted the service department and they said the common cause for that code is the gas cap not getting a good enough seal when tightened. Quick Fix and now the light is off. HOpe this helps.
talked to my mechanic and he said it was one of the vacuum lines or some line coming from the gas tank that has the sensor giving off the code. just needs to be re-calibrated after the jeeps computer was left without power from the install of the new engined that made it go a-wall, and yes i am at a .25 on my bretholizer after st. patts, and have not had a drink yet.
There is no sensor for the gas cap. What happens is the gas cap leaks either because it is loose, a bad gasket/o ring or the cap vent is defective. This causes the emissions monitoring system to throw a code indicating a leak in the system.
It is basically like a scale with constant normal weight is 1 lb. But when the system goes to 1.5 lbs or .5 lbs for a sustained period it throws a code.