The CTS in our engines has two completely separate sensors in the one package - this is why it has four contact pins. One feeds the dashboard gauge directly and runs off 12V, the other is connected to the ECU and runs off 5V. So the dash reading can be OK while the ECU can be seeing a false reading.
 
Hi All,

Just thought I would follow this up in case its usefull for anyone else reading these forums for this problem I was having.

Changed the sensor at the weekend, although I lost more coolant than expected (opened up the bottle to relieve the pressure then did it back up again) but I lost about 3/4 Litre.

Topped it all up, only tested it briefly but seems to have done the trick.

Hooked up to the laptop and my ECU temps are now consistant, no more variation in temps going from 100 to 0 then to 50 etc.

Hopefully its all sorted.

Thank you to everyone that posted to help me out, I really do appreciate it, and whats best - it cost me a very small fraction of a garage price (as they all wanted to do diagnostics etc)! I had one quote of £140 just for the sensor change!

Regards,

Craig
 
Bumholes!:lol:

I know,

I nearly spat my coffee out when they said on the phone! I was enquiring as I was completely new to this kind of thing and figured if its not much more, ill play it safe and get someone else to do it without the diagnostic charge etc