Corolla d4d engine temperature gauge went crazy

[Alexandruma]

Hey guys!

My 2005 Toyota Corolla 1,4 d4d has been running flawlessly for the last 40 thousand km. But two days ago the Check Engine warning light came up and the temperature gauge started to go up and down like crazy. The engine speed has also become chaotic and the moment I turn the ignition key on, the cooling fan starts cooling the engine even if the engine itself is completely cold.

I tried disconnecting the Battery for 10 minutes and then reconnecting it but to no avail. I suspect the problem is some kind of an engine temperature sensor that's gone berserk.

Did anyone have this problem? What is it and how can it be fixed?

Thank you all!

[Cookeh]

I can't help diagnosing it, but you could buy a cheap OBD2 reader from eBay/Amazon/wherever you please and check it for any error codes. That should give you more info on the problem itself and how to solve it.

[Alexandruma]

Turned out that some cables were ruptured and short circuited...