Dear Impala-
First, yes this is something that you need to take it to Chevrolet for.
The part that has failed is called the VSS or Vehicle Speed Sensor. It is located on the transaxle. This device tells the vehicle's ECM how fast you are traveling.
But this sensor controls a few other items too.
If your vehicle is equipped with Cruise Control this sensor tells the Cruise Control at which speed you desire to mantain on the highway. The VSS works in combination with the Crankshaft position sensor and Camshaft position sensor to determine engine RPM while the vehicle is in motion, again assisting the ECM during Cruise Control to maintian engine efficency and power.
The VSS also relay's milage information to your ECM too. If the Sensor completely fails, it may cause a Check Engine Light or Service Engine Soon Light to come on.
After the sensor is replaced the ECM, will need to be cleared of the trouble codes and reset so the computer can locate and recalibrate for the new sensor. All of this will be done before you get the vehicle back in your hands.
Depending on the milage of the vehicle this may be covered under Warranty by Chevrolet. Being the car is only 4 years old I would suspect that Chevrolet may cover it. You will need to contact your local Chevrolet Dealership for further details.
I hope I helped you out. Good Luck!
