Where is the coolant temperature sensor located on a 2001 Lexus is300?

Answer 1

That's a tough one. It's hidden and very hard to see. It's just under the intake manifold, (driver's side, of course), at cylinder #1 (front of the motor). There are two other sensors that you will probably unplug first before finding it. Lower and toward the oil filter is the oil pressure sensor. Just forward of the ECT sensor is another sensor that you will probably unplug first. They do not match the replacement part, especially since the plugs are different, and they take different sockets. The ECT sensor takes a 3/4" socket. When you get the part, there should also be a metal washer/gasket, like with an oil drain plug. I had to reuse mine.

To get to it, you reach basically through the dipstick tube to the block, just below the intake manifold. It might help to remove the dipstick tube, but I didn't. This will make more sense when you are in there. There is just enough room to blindly reach a hand in there and feel for it. You'll need to unplug it first with your finger tips. Feel around for the part you squeeze, like a lever, to loosen it and pull it off. This will take some fumbling. Then thread in the deep socket on an extension without the wrench first. After getting the socket on the sensor, you can put the wrench on and work it out.

If it's an emergency, you could jump the relay to get the fan going, but if you can, fix it right. The computer uses ECT data for timing and shift points.