check engine light comes on when gas tank hits 3/4 full on 1996 Volvo 960

I've been told it has something to do with the smog system. This has happened 3 times, each time when the gas gauge shows 3/4 of a tank.

Asked by for the 1996 Volvo 960
agree with #1
1 more answer , 1 more comment
Sounds like you have a bad spot on your sending unit,but we need the trouble code to give you a better guesstimate on what it could be.
Thank you - I will see if I can get the code.