97 Diablo some questions regarding LB RB light.

I was wondering if anybody may know why my diablo throws a cel, LB/RB light on when is warm outside and when is cold it turns off. It is a 97 roadster all stock except has aftermarket mufflers and gutted rear cats.
It disappeared for the winter and as soon as it got warm this spring it turned back on and both left and right bank stayed on until recently,when outside temperatures dropped in the 50's. I was told originally its due to my exhaust but I think it is affected by the outside temperatures.