Check engine light came on

2012 MERCEDES BENZ C250
180,000 MILES • 4 CYL • TURBO • AUTOMATIC
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DSALAS817
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Check engine light came on and it hooked it up to a computer turned out to be the camshaft position sensor. i replaced them both to no avail and the light came back on. took it a mechanic and said the light could be from loose timing chain and the sensor not reading right. plus the chain was noticeably loose when i turned the car on. i could hear it. so i replaced that and new tensioner as well. but now the light is still on and i am getting a subtle constant rattle from the engine. I do not know what I am to do now.
Dec 20, 2018 at 4:53 PM
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JACOBANDNICKOLAS
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Hi and thanks for using 2CarPros.

Did you replace the timing chain? Also, can you provide the codes that you are getting?

Thanks,
Joe
Dec 20, 2018 at 6:10 PM
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DSALAS817
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Yes, I have replaced it. Code p0340.
Dec 20, 2018 at 7:14 PM
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JACOBANDNICKOLAS
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  • 110,175 POSTS
Welcome back:

If the same code still is coming up, I question if the timing is exact or if there is an issue with the tension-er or one of the cam adjusters. What I suggest is to recheck timing to start. I attached pictures below for you to review. Please confirm that the correct mark was used for timing on the cam. Also, reconfirm that the tension-er is working properly. If you are hearing noise, I suspect either the chain has come loose, the tension-er has failed, the rail is bad, or something is loose on the cam adjusters. If the any of the things I mentioned has failed, it will set a camshaft position sensor code.

Let me know what you find.

Joe
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Dec 21, 2018 at 4:57 PM