# 2007 Sentra starting problems



## thorton22 (Mar 25, 2015)

Problem: 2007 Sentra turns over but will not start. It is throwing out a P0340 code so I replace the camshaft position sensor to no avail. If I unplug the wires from the sensor harness, sometimes it will start. I have to go through a procedure of plugging/unplugging the harness at the sensor to get it to start eventually. Sometimes it starts with the wires connected, more times than not it starts with the wires unconnected. 

I have had it in to a local shop and they said that there is continuity at the sensor. They told my that it may be a timing belt issue. Before I dive into having that done, I'd like to explore any/all other (less expensive) options. Any help is greatly appreciated!

-Tony


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## rogoman (Dec 16, 2004)

It's always best to replace both the camshaft position sensor and the crankshaft position sensor together. Always buy OEM replacements from a Nissan dealer; aftermarket replacements have been known to fail early or be DOA.


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## thorton22 (Mar 25, 2015)

Thank you, Rogoman. I will try replacing the crankshaft position sensor also.

I am starting to notice a bit of a pattern. With the sensor unplugged, the car will start occasionally. When it does not, if I plug the sensor in, turn the key, the engines fires quickly and then shuts off. If I then unplug the sensor (camshaft position), the car will start after a couple seconds of turning. Would this type of behavior point to a sensor problem?


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## rogoman (Dec 16, 2004)

You're throwing in another variable in your diagnosis mix. The first thing you need to do is get rid of the P0340 fault code. There are several things that could cause the fault code:

- Harness or connectors.
- The camshaft position sensor circuit is open or shorted.
- The camshaft position sensor itself is bad.
- The camshaft signal plate is dirty or damaged.


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## smj999smj (Jan 1, 2006)

First of all, 2007 Sentras don't have timing belts and haven't since 1988. Second, if you are setting a code, there is a diagnostic procedure for that code in the factory service manual that will give you step-by-step directions on how to test and isolate the problem. Since replacing the sensor didn't fix the problem, the next step would be to follow the diagnostic procedure. You can usually locate a downloadable service manual on the internet for free. You'll need the "EC" chapter for engine control. NissanHelp.com may have one in their "knowledge base" or you might find one at Nico Club's site, or forums dedicated to the B16 Sentra. I also agree with rogoman in that it's best to stick with genuine Nissan sensors; I've personally have run into a few faulty, "new" aftermarket sensors.


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