Coolant Temperature Sensor

[Guest neil17]

Im having problems with my C3 coolant temperature senor display. when u first start the car on a cold mornin. The display goes through its intial sequence and then starts normal.

Then if you give it a few seconds the temperature goes to maximum and bleeps at you even though the engine is cold.

Aswell after you have bin driving and parked up when u start the car again when it is warm. It goes through its sequence and when u start the car it shows the correct temperature but then problem occurs again.

 

I have replaced the temperature sensor and the problem is still there.

 

So i had a professional look at it at my dads work. but he said there were no errors codes showing up on the diagnostics. I honestly dont know wht to do now. He mentioned about replacing the dash display or even the ecu. but i didnt want to replace then and the problem be still there, as they cost just a little! :unsure:

 

Can anyone suggest anything that could help? Thanks.

[paul.h]

Welcome to the forum.

On the 1.4 petrol there are 2 temperature sensors at the left hand (gearbox end) side of the cylinder head. The one on the top does the dash gauge and the one on the side is a high temperature switch. On high temperature they both have the same effect (if I have read the wiring diagram correctly) of starting the radiator fan and setting the gauge to full and giving the high temperature indication. So if the fan is also coming on, chances are the other sensor is at fault - could be tested by disconnecting the sensor wiring plug which should then drop the indicated temp back to cold when the engine is started - bridge the plug terminals and should go back to high temp.