# 08 Nissan Sentra "HARD TO START / NO START" P0340 CODE



## robmx57 (Oct 30, 2017)

Hello everyone and thank you for welcoming me to your Forum. My GF has an 08 Nissan Sentra, base model, not sure of the engine in this. In the recent months, it has obtained a hard to start / no start issue. The OBDII code shows a P0340 (Camshaft Position Sensor). I replaced both the Cam and Crankshaft position sensors with no avail. I recently unplugged the camshaft position sensor and tried starting it, and it did after some crank time and a little gas pedal. I plugged it back in and tried again with no luck. I am starting to wonder if I have purchased a faulty sensor. Is there ways to check the sensor with a multi-meter? if so, what should I be looking for on the sensor pins? What voltage should the ECU be sending to the sensor? Also, I read on here that there is some kind of detection plate on the camshaft itself? Should I pull the valve cover and inspect this for debris? Any help / insight on this issue would be GREATLY APPRECIATED!!!!

Thank you,
Rob


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## rogoman (Dec 16, 2004)

If you used aftermarket cam/crank position sensors, that may be your problem; aftermarket sensor many times don't work correctly or are DOA. Always use OEM sensors purchased from a Nissan dealer; they sell a kit that includes both sensors.

There is a detection signal plate on the camshaft end. You can pull the valve cover and inspect for accumulation of debris on the plate.


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## smj999smj (Jan 1, 2006)

You can test the sensors using an ohmmeter. The spec would be in the factory service manual "engine control" section. You might found a downloadable section in our "knowledge base." I know on some models, the spec could be different depending on the manufacturer, like Hitachi vs. Mitsubishi. I'll second what Rogoman says in regards to aftermarket sensors; stick with genuine Nissan or Hitachi brand.


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## robmx57 (Oct 30, 2017)

So wanted to give a status update. I checked resistance between the three terminals on the sensor connector, while still connected to ECM, and had resistance between all three no matter what combo I checked them in. I unplugged all the ECM connectors, and checked it again, no resistance. I would suspect to have an issue with either the ECM connector or the ECM itself. I cleaned connector pins with electronics cleaner and plugged it back in to the ECM and the car ran perfect. I tried it again the next day, and it was doing the same thing again. At this point, I am leaning towards the ECM being bad. Any thoughts on this?? Thanks again for the help!


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## smj999smj (Jan 1, 2006)

You don't check cam and crank positions using an ohmmeter while still connected to the ECM; it's a good way to fry the ECM! They need to be unplugged. I would highly recommend you find a downloadable factory service manual.


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## robmx57 (Oct 30, 2017)

Sorry, Should have been more clear. I checked the sensor connector, with the car off, still connected to the ECM...


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## robmx57 (Oct 30, 2017)

I wanted to give an update on the status of this post. I changed the Cam sensor with a Beck / Arnley sensor, purchased from Rock Auto. I though the problem was fixed because it started right up and ran good the first couple days. After that, the same issue was back. I am not going to pull the valve cover off and inspect the camshaft reluctor for debris / build-up. The next step I think I am going to do is an ECM swap. Please if anyone has any other ideas let me know!

Thank you!


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## rogoman (Dec 16, 2004)

robmx57 said:


> Sorry, Should have been more clear. I checked the sensor connector, with the car off, still connected to the ECM...


What SMJ was saying: Physically unplug the harness connector from the sensor. Also when using an ohmmeter probe, make sure the engine is shut off and disconnect the negative (-) cable connector from the battery. Using an ohmmeter probe to perform resistance measurements introduces voltages into the system that may harm the ECU and other electronic components.



robmx57 said:


> I wanted to give an update on the status of this post. I changed the Cam sensor with a Beck / Arnley sensor, purchased from Rock Auto. I though the problem was fixed because it started right up and ran good the first couple days. After that, the same issue was back. I am not going to pull the valve cover off and inspect the camshaft reluctor for debris / build-up. The next step I think I am going to do is an ECM swap. Please if anyone has any other ideas let me know! Thank you!


It's very unlikely that the ECU is bad because the car ran good for several days; during that time the car went through many cycles of cold and hot, idle periods, acceleration periods from slow speeds to high speeds and shutting the car off and on again. I would examine the various engine harness connectors for tightness and possible oxidation on the pins. Also examine all the ground points for tightness and oxidation; in particular, insure that the battery terminals are clean and tight. If all else looks good, then replace the ECM as a last resort.


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## robmx57 (Oct 30, 2017)

So as I was removing the air intake tube (tube from air box to throttle body) I noticed the bottom of this tube was torn a little. I replaced this tube last night, as well as the spark plugs and the car started right up and ran pretty good. I let it get up to temp. and it ran good until then. I then let it cool back down, and tried it again, and again, it started up fine and ran good. I am going to let my gf go ahead and drive it and we will see! Thanks for every ones help!


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## robmx57 (Oct 30, 2017)

Update: I replaced the ECM, I'm pretty sure it needs flashed though. The car just turns over and acts like it isn't getting any fuel. Is this a common symptom of an ecm that needs flashed?? Thanks!


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## smj999smj (Jan 1, 2006)

I'm not sure if the key chip memory is stored in the ECM or BCM on this year/model? If it's stored in the ECM, the keys will need to be initialized otherwise the security immobilizer system will disable the fuel pump. If it's stored in the BCM, that shouldn't be an issue and you "may" need to flash the ECM. If it was a brand new ECM from Nissan, I believe they do often come in need of flashing.


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## robmx57 (Oct 30, 2017)

I managed to get the car running off of the old computer and got it to the dealership for key programming work. He seems to think it could be a mechanical timing issue. I should find out later today or tomorrow. I will keep you all posted on what the verdict is.


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## robmx57 (Oct 30, 2017)

So went to pickup the car from the dealership after they changed the ecm and said they started it about 20 times with no issues. Wouldn't you know, when we went to start it, same thing. Acted like it wanted to start and nothing. They hooked up the scan tool and there were no codes and when he tried it it started right up. I am pretty lost at this point. What is the oem cam pos. sensor manufacturer for this year and model? The dealership wants 130$ for it and I know it has to be cheaper somewhere else. I'm not sure if it will fix it or not, but at this point I am clueless. Any help or insight is always appreciated! Thanks in advance


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## smj999smj (Jan 1, 2006)

Hitachi and Mitsubishi make most of Nissan's cam sensors. It's likely Hitachi in your vehicle's case. Have you tried checking the price at a Nissan dealer's site, like CourtesyParts.com or NissanPartsDeal.com?


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