Cadillac Repair Questions? Ask a Mechanic for Answers ASAP
More than likely you have a bad crank sensor. Very common.
Have had many with no codes, (some set a code but most do not) and no way to verify the problem but it has fixed every one.
Like I said it's not for sure but I have never had any thing else cause this on this vehicle.
It's not that big of a job. You have to get the crank sensor from the dealer and it's around $60.00 i think. Then you could just have someone install it. It goes in the drivers side of the engine block and the wire goes up behind the motor and connects to the harness at the rear of the valve cover. You need a hoist and the engine should be cold. It's about 1 hour labor.