Temp sensor fault 17664 on u281 reader cupra tdi

[vindiesel]

Evening fellow seat drivers, vin diesel checking in after break from filming. Bit of a bitch have had a warning light come on which have been ignoring for past few months. Car drives fine just starts a bit shitty on occasion.
Any road bought a cheapy crappy reader that I have plugged in and gives a code 17764 which I think translates to a coolant temp sensor.
Does anyone know if this is easy to change and whether the 17764 is a coolant temp sensor. Notice my mpg seems to have suffered a bit since this has come on.
Is there a guide on here for changing the beasty, also will it harm the car if I don't change it?
Too fast too furious vin!

 

[Seatmann]

Assuming this is the Mk1 and has the PD150 engine I think it might be at the rear left of the engine in the flange that bolts onto the end of the head. That's the gearbox end, right at the back of that coolant flange.

One of the symptoms of a bad sensor is the glow plug light stays on for ages rather than the usual few seconds.

 

[vindiesel]

Mines a January 2005 on an 04 plate, think its a buk engine, it is the early cupra tdi. Is there a guide on hear for changing or has anyone got a photo? Had a look on the site low info...for changing this sensor but I might be looking in wrong place. Cheers vin