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HDGENE
HDGENE, Ford Senior Master/Diesel/Trans
Category: Ford
Satisfied Customers: 5493
Experience:  25 years Auto experience, Ford ,GM, Chrysler, Asian & European
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Failed cylinder head temperature sensor....how to differentiate

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Failed cylinder head temperature sensor....how to differentiate sensor disrepair versus actual engine problem. All guages read fine, but code p1299, p1285 documented with troubleshooting on 2000 ford excursion.
Sometimes, these sensors fail, often times the wiring gets chewed up by an animal making a nest under the hood. Best way to know if you have a sensor fault would be to monitor the live sensor data with a scan tool and see what temperature its indicating. It could be reading -40 degrees F and setting a fault indiciating a shorted sensor. If the vehicle was overheating, you should see the temperature gauge indicating that. Assuming the temp gauge is working properly. It can also be tested with a scan tool to perform a gauge sweep test.
Customer: replied 4 years ago.

where does one obtain a scan tool? the ford dealer has quoted me700.00 to evaluate the sensor. 150 in parts..550 in labor and will not guarantee this will fix the problem. is this a fair price in your opinion?

The dealer price is in line since you need to remove the intake manifold to gain access to the sensor itself. You can shop around and see if a non dealer would perform this repair and diagnosis cheaper. Most local auto parts stores sell and/or rent scan tools with a deposit put down that they return when the tool is returned. You mainly want one that has the option to look at live sensor data, not just a simple code reader.
Customer: replied 4 years ago.

thank you. one further question. if the sensor only is bad and the engine is not overheating would it hurt to drive it until the appt to have it fixed?

It would be ok as long as the engine isnt overheating, it uses other sensor inputs to calculate engine temp when the main sensor fails. Long as it isnt giving a false reading that it is running too cold, then it cold richen the fuel mixture up and run poorly/loss of fuel economy
Customer: replied 4 years ago.

driving has resulted in a reserved slow down mode with enough power to get off the road safely only. all engine lughts come in. when engine is turned back on all lights off with the exception of the check engine light. all guages are normal in the normal range when this happens. your thoughts?

The engine does enable a fail safe mode if the sensor is indicating the vehicle is overheating by limiting fuel injector flow and such hence your reduced power. This is a fail safe limp home driving mode, if it is acting in this fashion then it should be fixed to enable full use of the vehicle
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