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Q: Check engine light will not shut off after many repairs and it reads it has a faulty crank shaft sensor.

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Awhile ago, a mechanic found my crank and cam shaft sensors partially melted, so they replaced them. The check engine light was still on, but I know that for my car if the sensors aren't from the dealership they will give faulty readings, so I had them put one on from the factory. Check engine light still on. One mechanic said it could be a faulty wire somewhere in my car, another said it is the cars computer, and the third still thinks it's the sensor. Any help would be greatly appreciated!! Thank you!

My car has 106000 miles.
My car has a manual transmission.

A: I have about 8 years of experience working ...

I have about 8 years of experience working at a Hyundai dealership and I’ve never come across this before. The crankshaft sensor was a fairly common repair, but there was always related symptoms to go along with it. The computer needs the input of the sensor for the engine to run. If the sensor, wiring, or computer fail, the engine will not start. I’ve seen the sensor cause the engine to stall, especially when the engine is hot. In your case you have the code for the sensor, but you are not experiencing any problems with the engine. I find this peculiar.

I’m glad you decided to get the parts from Hyundai. That eliminates the possibility of a low quality aftermarket one. Are you sure that the crankshaft sensor trouble code is the only code in the computer? The mechanics you speak of, are they all at the same shop? Or did you get several opinions from different shops? If they are from the same shop, I would get another opinion if you haven’t already. I would take note of any and all codes that they found.

The problem could be the wiring, or the computer. Both can be tested with the proper information and tools. One more possible cause is a loose or broken "tone wheel." This is very uncommon. This is the part that is attached to the crankshaft that the sensor reads. If it moves from its intended position, it would cause a crankshaft/camshaft correlation code. Another option at this point is to take the car to a Hyundai dealer. I have seen aftermarket scan tools not communicate properly with the cars computer. They could be giving false information. And a third option is to hire YourMechanic. We can visit your home or office to provide a diagnostic for your car’s Check Engine Light and make the needed repairs to have this issue resolved correctly.

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