The Check Emissions and SH AWD Warning Lights pop on intermittently on my 2009 RL. They sometimes turn off when I fill up the gas tank, and then later, they'll pop back on. I know a loose gas cap can cause the emissions light to go on, but can it also cause the SH AWD light to come on? Are they on the same circuit? I did have my gas cap replaced recently. Could that also be causing the lights to go on?

 

It could also be the usual electrical gremlins and a restart after gas filling is merely a ctrl+alt+del. Especially if the AFS light also comes on...

Check for a weak battery/terminals and the grey wire connector under the steering column.

There's a zillion threads here about it.