The fuel pump secondary control circuit deals with the fuel pump driver module (another word for computer) which is use to regulate the fuel pump pressure. By using a fuel sensor located in the fuel rail, the engine computer can regulate the fuel pump pressure by monitoring the fuel pump duty cycle.Using this duty cycle range, the computer can determine when to shut off or increase the fuel pressure for optimum engine performance. Therefore, if the duty cycle is below or higher than the targeted range,it will set a code related to the fuel pump secondary control circuit . When this happens, the fuel pump driver module will set at a default usually set at 100 % duty cycle. For basic test, check connections of the wiring/grounds.
#1 starting changing the relay is good thing, but the question is "Do you have power to the relay?"if there is no power, check the fuse #30, in the battery junction box, under hood.(see diagram).check also relay ground.
If there is power to the relay,
you have 3 splices and 2 connections from the relay to the computer, check them.
if they are all good and not disconnected, the problem might be in the pcm.
They are not parts, they are connections used as ground by the computer.you cannot repair them yourself, let the dealer fix those, and probably reprogram the pcm.
(I'm sending this diagram to your email)