car says: Action required, steering assist reduced, drive with care
Take it in Monday morning. Do not risk your life, or the life of others .
Could be anything. One post on a Cadillac forum said it was caused by a bad thermostat. Go figure. Since it has electric power steering I’d be inclined to suspect a marginal alternator.
Is there any ambiguity in that warning at all for you? Seems very clear to me.
It tells me you should get the car in for service immediately. While you can drive it to service, not tow it, do so with care.
I have a hard time imagining that anyone could interpret that message as anything other than the imminent need for repair, preferably from a Cadillac dealer.