P340 ERORR

Blazer

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hello
my ford mustang 2006 4.6 gt with 155 thousand miles is giving me a P340 error, namely the camshaft position sensor, I replaced the sensor, adjusted the alternator and it charges fine, I also replaced the battery and went for a drive after 30 minutes when I turned the car off and on again the light came back on, the engine runs perfectly, the chain is not heard, what could be the problem?
 

86GT351

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hello
my ford mustang 2006 4.6 gt with 155 thousand miles is giving me a P340 error, namely the camshaft position sensor, I replaced the sensor, adjusted the alternator and it charges fine, I also replaced the battery and went for a drive after 30 minutes when I turned the car off and on again the light came back on, the engine runs perfectly, the chain is not heard, what could be the problem?
What do you mean you "adjusted" the Alternator?
 

Dino Dino Bambino

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hello
my ford mustang 2006 4.6 gt with 155 thousand miles is giving me a P340 error, namely the camshaft position sensor, I replaced the sensor, adjusted the alternator and it charges fine, I also replaced the battery and went for a drive after 30 minutes when I turned the car off and on again the light came back on, the engine runs perfectly, the chain is not heard, what could be the problem?
Your alternator could have a defective diode that's allowing a small AC current to leak into the engine harness. If you have a digital multimeter, you can perform an AC ripple test in your own driveway. There are plenty of instructional videos in YouTube.
If it turns out to be bad, you'll need a replacement alternator. Do NOT buy a parts store unit with a "lifetime warranty" 'cause they're invariably junk. Either get a Motorcraft OEM replacement from the Ford dealership or an 09-10 GT OEM Denso unit. If you need a higher amp upgrade, PA Performance alternators are reputedly good.
 

StockishS197

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by mistake I did an alternator test and it's ok
Make sure they test specifically for AC ripple.

The alternator can be charging fine and produce high levels of AC current from a failing diode, which is a far more frequent cause of the P0340 than the CMP sensor itself actually failing.
 

Laga

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6 months ago I had the same code. It was a bad diode. The instructions are online, you disconnect the wires from the alternator and test current from positive post to body of alternator, then reverse.
 

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