The check eng light went on in my 1998 V70XCO . It has 110,000 mi. My mechanic said the test computer said it was the gas tank cap. He put a new one on and reset light so it is not on now. He said if it comes back on problem could be the J Tube. Although he said he could not see J Tube . So if it has one he would have to drop rear end to access it. Does anyone know if it has one, or how to replace one ? [/align][/align]Thank You[/align][/align]Walter[/align]

 

If that is is he is right you will have to drop the rear susupension to access it.
But it could be alot of other things as well.
The system will have to be pressurized to find out for sure.