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Q: Code p0128

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I have had a po128 code for as long as i have owned my escape. Replaced the thermostat twice and the cylinder head temp sensor. From everything i have read there is no coolant temp sensor and i cant find one. But i have a scanguage in my car that reads CHT and coolant temp at different temperatures. Its a 2.3l inline 4. What else could be causing my problem and or where exactly is the coolant temp sensor.

My car has 140000 miles.
My car has an automatic transmission.

Your vehicle does not have a coolant sensor and uses the cylinder head temperature sensor to do both jobs. The system uses this sensor to sense both the coolant and head temperature. If your vehicle fan is running all the time with A/C on or off, this can cause the temperature to not get above 170 degrees within a set amount of time. You should have the system checked by a certified technician, like one from YourMechanic, to diagnose the trouble code firsthand and scan the data to see what could cause the vehicle engine to run too cool.

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