Coolant Sensor Issues, VCDS code and fans running, BKD G62 + G83

[TdiBlacky140]

Ok, I have a issue with the temp gauge in the car behaving a bit erratic. It sits at the normal 90 degrees for most of the time, but sometimes it flies all the way to the overheating end of the scale for a second and the STOP Coolant warning chimes up on the dash display, before the gauge then returns to 90 mark. Other times its drops from 90 to a lower point on the gauge and then returns back to 90 quickly. Sometimes it wavers around the 85-90 mark.

Sometimes the cooling fans stay running too with the ignition on and the EML comes on too.

This is the BKD 2.0L engine, it has 2 coolant sensors one at the side of the engine above the gearbox which I believe is G62 and one in the thermostat plastic pipe at the front left of the engine which I believe is G83. Please correct me if I have them sensor number mixed up. They are both the same sensor, 1 part no. and are 2 pin grey sensors.

The actual coolant fluid level is fine too by the way, never changes.
I have replaced the sensor above the gearbox which I believe is G62 with a genuine VW one and still have same problem.
I fitted a new genuine VW thermostat in the last 6 months too so I'd like to think that's ok, doesn't seem to be a problem with engine getting to temp, same warm up time in mornings.

Here's the VCDS fault log info:
000279 - Engine Coolant Sensor G62
P0117 -000 - Signal too low - Intermittent

Freeze Frame:
Temperature 100.8 degrees
Temperature 80.1 degrees

I've 3 main questions:
1 - where is the G83 sensor value to be found in VCDS? I can find G62 in about 3 different places but no mention of G83?
2 - In the freeze frame data, why are there 2 temperature values of 100.8 and 80.1 and why are they different? Is 1 of them values the G83 value?
3 - Does the gauge in the car read off the G62 sensor?

I'll probably replace the G83 with a new genuine Vw sensor but is there anything else I can check / test to try determine what the problem is or i whether or not the G83 sensor is actually faulty or not? The new G62 coolant sensor is hardly faulty?Also, probably stupid question but how long can I drive the car with VCDS plugged in or does it matter, like can I leave my Vcds connected for an hours drive to monitor the coolant sensor reading?
Hmmm, any advice appreciated.

[TdiBlacky140]

Anyone able to answer some of my 3 questions even? Hopefully going to get time to look at the car when I get some time over the weekend.

[Jon44w]

I changed a g62 last week on an Audi A4 because it put the engine light on and was giving an erratic temperature reading on the dash and all is good now. So to answer question 3 I believe yes the reading on the dash is taken from the G62

You can drive your car with VCDS plugged in for as long as you want. Just make sure its not a knock off cheap illegal clone copy or youll be wasting your time as false readings. wrong descriptions on measuring blocks etc and it will melt your head, been there done that and never again.

[Crasher]

Whatever the dash gauge says ignore it, the only way to know what is going on is to view the data from the dash and engine ECU’s. I have seen the real readings say 77 when the gauge says 90 and still say 90 when the data showed 117.