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HDGENE, Ford Senior Master/Diesel/Trans
Category: Ford
Satisfied Customers: 5496
Experience:  25 years Auto experience, Ford ,GM, Chrysler, Asian & European
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I have a 2010 Ford Fusion 2.5 engine The temperature goes up

Customer Question

I have a 2010 Ford Fusion 2.5 engine
The temperature goes up and and then engine turns off
And we replace the head temperature sensor because we were told that engine doesn't use a temperature sensor at all
After replacing it the sensor runs but the temperature nidle stays down all the time
The Ac don't work but it was working before that incident
And even thou the nidle is up showing is overheating but in reality is not
Submitted: 1 year ago.
Category: Ford
Expert:  roy replied 1 year ago.

good evening my name is ***** ***** I will assist

does the car still overheat???


Customer: replied 1 year ago.
the thing on the dash it goes all the way up and engine turns off
Customer: replied 1 year ago.
But the car is not actually overheating
Customer: replied 1 year ago.
fan runs at high speed line when u turn the Ac
Expert:  roy replied 1 year ago.

how do you know it is not overheating??? the heat sensor is doing its job protecting the engine from damage and the gauge is verifying it is hot


Customer: replied 1 year ago.
Because it happens when I start the car in the morning the thing stays down and doesnt go up at all but the fan is running like crazy
Expert:  roy replied 1 year ago.

is there any white smoke out the exhaust???


Customer: replied 1 year ago.
We install the the sensor tonight and the car is started right away but I thought a couple minutes the needle thing went up in the engine shut off so we wait a couple more minutes we started back up the car enough that a little bit it happened the same thing The AC is not working but the cooling fan runs all the time a high-speed
We looked everywhere we couldn't find it temperature sensor like other vehicles so I was told that this going to be cool it doesn't use a temperature sensor is only they had temperature that works as both
Expert:  HDGENE replied 1 year ago.

Hello, you replaced the cylinder head temperature sensor? How many miles are on the vehicle? Do you have good heat when you turn the heat on? Full of coolant no leaks? Can you post the 17 digit in number so I can check a few things?

Customer: replied 1 year ago.
I replaced that sensor cuz I was told that's the one that reads the temperature
About 120k miles
Yes the heater Doesn't work
Full coolant
Expert:  HDGENE replied 1 year ago.

Ok does the engine run long enough for it to reach normal operating temperature or does it shoot right up to overheat? No codes stored in the PCM? Do the heater hoses get hot?

Customer: replied 1 year ago.
we drive it for a while but it only goes from bring all the way down to all the way up all of the sudden
And when that happens is when the engine dies
We got it to work by bypassing the connector with a wire but the indicator stays down all the time but Ac don't work and fan runs high all the time
Yes the hoses get hot
Expert:  HDGENE replied 1 year ago.

Heater hoses hot should have heat, no codes stored in the pcm if checked for codes?

Customer: replied 1 year ago.
Ill take to the mechanic to see what code comes on ill let u know
Any idea what could be the problem so far ?
Expert:  HDGENE replied 1 year ago.

Either a shorted circuit for the cht sensor causing the gauge to raise be one thing but the lack of heat could be an issue with a blend door motor if the hoses are hot.AC will be disabled if engine is running hot according to gauge and cycle fans on

Customer: replied 1 year ago.
What's the cht sensor ?
Is there an actual temperature sensor in this car ? I've looked everywhere and that's the only only I found , is located between the cylinders
I really need the solution to this problem thou
Tell me what can we do or try ??
Expert:  HDGENE replied 1 year ago.

Normal Operation

The PCM uses the Cylinder Head Temperature (CHT) sensor to measure the engine temperature. The Instrument Panel Cluster (IPC) receives the engine temperature data from the PCM over the High Speed Controller Area Network (HS-CAN) communication bus. The IPC monitors the engine temperature data received from the PCM and commands the temperature gauge indication with a corresponding movement of the pointer.

The non-hybrid and hybrid temperature gauges appear differently but essentially function the same. The non-hybrid gauge is an analog gauge with a needle that points to a specified area of the gauge depending on the data received from the PCM. The hybrid gauge is a digital display that appears as a thermometer. The fill color of the thermometer is blue when the temperature is between the cold and normal ranges. When the temperature indicates an overheating condition, the fill color turns to red.

Customer: replied 1 year ago.
There is a code
Expert:  HDGENE replied 1 year ago.

Ok for one if you didnt know this vehicle has a branded title, meaning it has been probably in a major wreck and reassembled. Carfax can tell you more regarding that, there is a technical service bulletin im attaching mentioning corrosion inside the cht sensor connector and how to inspect& repair if needed.

Customer: replied 1 year ago.
There is no sign of corrosion or water in the CHT it's all clean
Expert:  HDGENE replied 1 year ago.

Then with a new sensor installed and verifying the engine temperature isnt actually overheating. Since its a branded title, there is a possibility of a wiring issue with the vehicle. You should run your own wiring from the CHT sensor to the PCM to eliminate a wiring problem. If it still does the same thing bypassing the harness, it would be an issue with the Powertrain control module itself. If the engine is actually overheating as the temp gauge says it is and the cooling fans are working it is a possible issue with the water pump impeller damaged and not circulating water properly. Im thinking its more of an electrical issue. The blue wire is the signal return for the sensor pin 39 to the pcm. SInce the green wire to the sensor is supply power for other sensors and not flagging other codes I dont suspect that being an issue but you can jump from one of the other sensors to the green wire and return wire to the pcm to see if it changes operation.