CTS= Coolant Temperature Sensor it's the blue sensor at the back of the head on the inlet side, this is an important input to the ECU as it's info is used to determine the base level of fuel injected from freezing to boiling, they do go out of scope after a while so if you were worried about sensors, this is one to do.

Oh that is good then someone may have already done it, make sure it is an override switch though NOT controlled solely by the switch otherwise it's reliant on you turning them on opposed to the automated system.

The fuel pump voltage needs to be checked UNDER load and so you need to give it some stick whilst monitoring the voltage, the easiest way to do this is to run some power from the connections using two bits of wire to a meter inside the car.

Yes SECS monitor replaces the clock in the center console and has two buttons on it, the screen is a common problem, a guy called Simon (ECU Monitor Enthusiast) on here used to repair them but not sure he does now, also Mike at R&B Motorsport used to as well I think.

Martin