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HighwayRepair
HighwayRepair, Auto Service Technician
Category: Ford
Satisfied Customers: 665
Experience:  12 Years Auto Repair Experience. Owner/Operator of Highway Auto Repair, a mobile automotive repair business
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2003 ford focus 2.3 wont start after driven when hot. Raise

Customer Question

2003 ford focus 2.3 won't start after driven when hot. Raise the hood let set for 15 minutes will start. What is the solution?
Submitted: 7 years ago.
Category: Ford
Expert:  HighwayRepair replied 7 years ago.
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HighwayRepair :

The most common cause of your complaint is a faulty Crankshaft Position Sensor or "CKP" sensor. Do you have access to a digital multimeter? This sensor is testable with the correct equipment, unfortunately this sensor is more involved when replacing than most, as ford has it designed so that this sensor must be indexed when installing. I can provide you with replacement procedures, but i highly recommend having this sensor replaced by a service facility instead of replacing it yourself.

JACUSTOMER-o2nmp6kh- :

What is the procedure for testing the CKP? I will get some one to replace it for me but I would like to verify that it is defective before I replace it. I will get some one to check it for me(the sensor ) . I am not s mechanic but I have a background in electronics.

HighwayRepair :

I can get that information for you, before i do that though, let me clarify something. The sensor will have to be indexed if it is removed, whether it is replaced or not. It can be tested while still on the vehicle, but usually the crank sensor would be removed to test on a bench. With this particular sensor you would want to test it still in the vehicle, so if it tests "ok" you don't have to re-index it.

HighwayRepair :

the crankshaft position sensor is a magnetic induction pick-up sensor, which basically means that it has current pass through it to create a magnetic field. The sensor also has a magnet on the end of it, when the crankshaft spins past it the metal on the crankshaft "breaks" this magnetic field. The computer measures how fast this field is being broken to determine engine speed where in the engines firing order it is currently at. When these sensors fail most of the time what happens is an electrical open forms inside of the sensor itself, Electrical resistance goes up as heat increases, so when these sensors fail they usually will run cold and have an electrical open when hot. That is why your vehicle runs until it's hot, then turns off, then will restart when it has cooled off again.

HighwayRepair :

because of the above information the sensor needs to be tested while it is hot

HighwayRepair :

Step 1 will be to locate the crankshaft position sensor on the vehicle ( i will provide a component location chart at the end of this post). After the sensor is located turn the vehicle on and let it run until it gets hot enough to turn itself off. then remove the electrical connector from the crankshaft position sensor and test for continuity (also known as ohms or resistance) between each of the two pins on the crankshaft position sensor. If this value reads O.F.L "Out of Functional Limits" or an extremely large number I.E. 20k Ohms (which would be 20,000 ohms) this sensor is faulty and needs to be replaced.

HighwayRepair :

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HighwayRepair :

Hello, did you still need assistance with your question?