ASR code, limp in mode cause
lots of things CAN cause the problem. The message is saying 'you asked for the throttle to open, but I could not do it because when I tried, the proper signals, which must travel over the Car Area Network (CAN) did not result so I am uncertain what has gone wrong so I am not opening the throttle and am shutting down to a safe limp -home mode.'
Most probable is a defective electronic throttle actuator (or Electronic Accelerator Control "EAC") and it's integral wiring harness. Usually the insulation on individual wires in the EAC harness crumble to dust causing intermittent shorts. I believe these are a little under $1000 for your car. (For the 600's, there are 2 of them, and they cost some $2400 EACH!!)
If your are really unlucky, it can be the CAN wiring, which is in the main wiring harness, which costs $4,000 + installed.
When you push on the accelerator, you are moving a 'wiper arm' on a variable resistor in the EAC, which changes the signal to the engine control computer via the (defective) wiring harness through the Car Area Network (CAN). The engine control computer then sends a signal back through the CAN to the EAC servo motor to rotate (open)the throttle valve until the position sensed (another wiper arm and variable resistor setup attached to the throttle shaft, ) by the computer (signals traveling again through the powdered wiring insulation and CAN) is correct for the commanded accelerator position, AND the ASR (acceleration slip reduction) system and sensors are not indicating wheel spin.
You ask for more throttle, the computer gives it--provided everything works as intended. You ARE NOT opening the throttle directly, but only giving the engine control computer a request.