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Cam position sensor

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Hey, I've got a 2002 1500, with the 4.7 L. It's throwing a p0340 code which means cam position circuit malfunction. I've replaced my cam positioning sensor as well as checked all the wiring for shorts or breaks all is good. Also checked the crank position sensor, its good. The truck will start intermittently and run fine once it starts. But most of the the time it'll just turn over and not fire.....Help Thx Dusty
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A hard reset of the PCM won't help. The reason for the extended crank time is because the PCM is trying to figure out if the #1 cylinder is on TDC of the compression or exhaust stroke. Once it does, the engine will fire.
 

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Discussion Starter · #7 ·
Any help appreciated!

How and what did you check for besides continuity? Did you check for a short to power, ground, and sensor wires shorted together? Also, have you load tested the circuit?
Thx, I'm pretty new at this whole wiring thing. What exactly are the proper steps to check if my cmp wiring is working correctly. The code p0340 in the book says "no cam reference signal from the cmp sensor at the pcm. "
 

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The main thing with a dvom if you don't have access to a scan tool to clear codes is to snake a t pin like the upholstery needles your mom used...in next to the wire at the connector. This is commonly called backprobing and it causes no long term damage to the wiring. Once you have connection check for voltage on each wire with the key on and engine not running. There will be 5 volts supplied on one wire, 5 volts on antoher that is being switched to ground alternately while cranking and approximately .2 or less on the ground. If you see this it is working at the time your testing it.
 

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Another quick test while it is not starting is to find the wire that is the signal...meaning the one that switches...and it is shorted and never comes up past .3 volts you now know that the sensor or wiring is bad or the wheel actually is under the sensor. Bump the starter and if it never pops up to 5 volts.... I would unplug it and see if the voltage pops up to 5. If it does you know your sensor is bad. git u sum
 
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