Cam sensor

2006 NISSAN ALTIMA
120,000 MILES • 2.5L • 4 CYL • 2WD • AUTOMATIC
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JOE GAINES
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Had a cam sensor go bad and car went into limp mode. Replaced it with a NAPA sensor and the car ran great for about 59 miles then went into limp mode again. Replace the sensor with an OEM sensor but the car would not start. Replaced the sensor with a new Napa sensor and it still would not start. Put the old sensor in and car runs great. What is going on? Checked the wiring and everything checks out. Are some sensors not sensitive enough or is there a “special” sensor that will only work.
Oct 10, 2019 at 6:44 PM
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JOE GAINES
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As an update to this post, when I install the new sensor properly the car will not start but if I rotate it 180 degrees the car runs fine. The problem is, with the sensor rotated the mounting hole can’t be used. A month ago, I had the cams out to install a new head gasket. Is it possible to get the crank and cam sensors out of sequence?
Oct 11, 2019 at 7:03 PM
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JACOBANDNICKOLAS
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Welcome to 2CarPros.

Interestingly, the cam sensor is nothing more than a magnet. It shouldn't make a difference. I attached a picture below and circled the cam sensor. Is that the part you are referring to? If it is, check the wiring at the plug. I suspect you have a broken wire that is making contact when the switch is 180° off. Or, you got a sensor that isn't for this vehicle.

Let me know.

Joe
Oct 12, 2019 at 8:34 PM
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JOE GAINES
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I know this sounds weird. I rebuild classic cars as a hobby so I have a lot of time under the hood. This problem just blows my mind. I’m sure it’s the cam sensor and I have double checked the Nissan part number 23731-6N21A. The wiring was my first thought but I can’t find anything wrong with it. The old sensor works in the normal position and rotated but the new one has to be rotated 180 degrees to work. These are the new round silver sensors. I understand how the sensor works. It should work at any angle. I put a new head gasket on this car and had the timing chain and cams off but if something was wrong there it wouldn’t run like it does. With the new sensor rotated the car purrs like a kitten. I have tried three different sensors and all three are the same. Only the old one works normal. If you can figure this one out your a genius.
Oct 13, 2019 at 1:10 PM
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JACOBANDNICKOLAS
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Welcome back:

I understand your frustration. LOL Genius, no, but could you upload a pic of the original one that works and the new ones that are causing the problem? It may trigger something in my mind.

Let me know.

Joe
Oct 13, 2019 at 7:32 PM
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JOE GAINES
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I really appreciate you taking the time to do this. I know it’s hard to solve problems remotely. Attached is the pic you requested. The sensor on the bottom right is the one that works. It was in the car when I bought it. When the car threw a P0340 code I changed it out and that’s when all this started. The one on the bottom left is the NAPA one. The other two are OEM. In testing them I found that the OEM on the top left and the one that works attract each other when put head to head. The other two repel the one that works. I don’t know if this makes any difference. I retested the plug and it’s okay. The one on the top right came in a kit of two identical sensors. (The other one is in the crank position and works good.)The one on the top left says crank sensor on the package but Nissan says it is the same as the cam sensor. All three new ones act the same as far as having to turn them 180 degrees. Thanks again for your help.
Oct 13, 2019 at 8:55 PM
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JACOBANDNICKOLAS
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It's hard to tell. Like you said, they do look the same. I am going to get some advice from a friend about the magnets' polarity. I can't see how, but maybe that is the cause.

Joe
Oct 14, 2019 at 6:03 PM