# 2009 sentra 2.0 wont start



## 303640 (Jan 14, 2021)

So one morning the sentra cranked a few times before starting up. normally she just turns right on. It only happened once and the rest of the day it was fine. The next morning, It wouldnt start. It would just crank and crank. First thing i did was change the crankshaft sensor. but it still didnt start. it would turn over but wouldnt fire. So i pulled the air horn and sprayed some staring fluid but got nothing. So i thought maybe it was a faulty new sensor and swapped in a new one. same issue nothing, then i changed the camshaft position sensor and still nothing. I pulled the ecu and had it tested, it came bak in working order. Im stumped. does anyone have any ideas?


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## VStar650CL (Nov 12, 2020)

If there are no codes and no security lamp, suspect the MAF sensor or the ECM relay. Fuel pressure and the MAF are the two things the ECM has no way to double-check, so if the MAF is lying that could be your issue. If the ECM fuse is good (yes, check it first!) then a bad ECM relay will cause no codes because the ECM can't "wake up" to throw any. If the electric fan runs as soon as you turn the key, suspect a problem with the ECM power circuit. Lastly, is the security lamp lit solid when you turn on the key? If so, you have a bad key or IMMU, or some other issue with the NATS system. If so, _don't keep cranking it! _If you do, there's a good chance the ECM will commit _hara kiri_ and render itself permanently useless. Try having a new key programmed first (cheapest possibility). If the program won't take, suspect a bad IMMU.


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## steveX (Dec 20, 2019)




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## smj999smj (Jan 1, 2006)

First, check your fuses; sometimes the simplest of things is the problem. Also, make sure the plugs are not fouled and check for engine compression. See if you have spark. Since you tried starter fluid, it's likely not a fuel delivery issue. If all the basic checks turn up nothing, the next step would be to hit the factory service manual. The engine control section will have diagnostics for a crank-no start condition. NICO Club allows free access to their Nissan service manual database at their site.


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