This bulletin was provided by GM regarding 2014 and prior GM cars and trucks that feature RKE (remote keyless entry) and/or RVS (remote vehicle start).
Some customers may comment on poor or no transmitter range when using the RKE and/or RVS. In some cases, the range has been limited to a few feet.
Some aftermarket devices can cause frequency interference, which may affect the operating range of the RKE and/or RVS functions.
Inspect the vehicle for any aftermarket devices installed or stored in the vehicle. Examples include cell phone or USB chargers plugged into an accessory port, wireless gate remotes, wireless winch remotes, etc. Inspect all accessory ports and check all potential storage areas (instrument panel, glove box, center console, rear cargo area, under seats, etc.).
Remove any aftermarket devices and then evaluate operation of the RKS and RVS.