Chev dealer quoted me $640 to repair the problem. Seems very high for the sensors. Is that a fair price?
Remote Lock and auto engine start sensors are out on 2006 Chevrolet Impala
There may be a service bulletin from GM regarding the operation the remote system on your Impala. That does not necessarily mean it is covered under warranty but it does indicate there is a problem with the system that GM is aware of. Try and find out if the dealer is performing the repair as per a service bulletin. If that is the case try talking to the service manager about a "good will repair". If that does not work the next step would be to contact GM customer service.