My 4runner has 94K miles on it, and recently while driving I got the CEL. I went to auto-zone to read the error code, which came to P0115 (Engine Coolant Temp. Circuit Malfunction).

I have been driving it since then and noticed that the CEL light comes on intermittently. I also noticed that sometimes the engine seemed to rev up a little bit when I am idling at a stop light. The temperature gauge seems okay.

I had recently done the 90K mile service at the dealership, and also replaced all the belts and the water pump. It seems the problem started happening after that. I don't know whether it is just a coincidence or the dealership messed something up.

Does it cost a lot to replace the ECT sensor, or is the problem somewhere else? I have already spent quite a bit of money on the 90K service and timing belts. Is it an easy job? Do I need to go to the dealership, or any mechanic will do?

Any help and advice will be greatly appreciated.

-RJ