Hyundai Repair: check engine light is on, coolant temperature sensor, engine coolant

Question
QUESTION:  how to repair the engine coolant high input circuit
ANSWER: I'm presuming your description refers to code P0118.  This code can occur for several reasons:

1.  Engine overheating.
2.  Defective coolant temperature sensor.
3.  Open circuit in temperature sensor circuit.
4.  Short to ground in signal wire to temperature sensor.

If your car is overheating, you should diagnose and address that issue first.  If your coolant is low, you should check for leaks and repair any found.

If your car is not overheating and your coolant is at the proper level, it's very likely that the coolant temperature sensor itself is the issue.  In that event, you should replace the coolant temperature sensor.

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QUESTION: Hi,
My car is not overheating and I have replaced the coolant in the car. I would like to know where to locate the circuit input in question on my Hyundai Sonata 2001.I would like to try and do it myself before I take my car to the shop. Also can you tell me about how much it would cost to replace the sensor.

Answer
The circuit has two wires running from the engine control module (ECM) to the coolant temperature sensor.  The sensor screws into the coolant housing on the transmission end of the engine.

In most cases, you can probably expect to pay $100 to $200 to replace the sensor.