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I have a 2008 which I recently converted to a cummins 5.9 common rail. After the conversion everything on the truck worked peachy until one day the tachometer stopped working, as did the A/C.

Both the ford cam and crank sensor are adapted onto the cummins to allow the Ford "smart dash" to function.

I get a consistent P0341 in the ford pcm for "Camshaft Position Sensor A Circuit Range/Performance (Bank 1 or Single Sensor)"

I chased the P0341 according to https://www.motorcraftservice.com/pubs/content/~WV8E/~MUS~LEN/15/V8E5093.HTM


everything checked out until I got to V4 "CHECK THE CMP CIRCUITS FOR A SHORT TO VOLTAGE IN THE HARNESS"

where i find 2.5V at both + and - terminals of the cmp connector (Key on, engine off, sensor unplugged)

If voltage is found the chart says to locate the short to voltage in the harness.

I separated the harness and isolated the pair of wires for the cmp connector.

Under the tape, the pair of wires is sheathed in foil along with a bare wire which goes through the pcm connector and to ground, this is factory ford portion of the harness.

I checked for continuity between the two wires for the sensor while bending and jiggling the length of the harness and there was none. No damage to any of the wiring or signs of heat/ chafing.

I checked for continuity between both sensor wires and the bare wire and there was none.

There is never any voltage at the bare wire.

No bent pins or signs of heat in the pcm connector.

Voltage at two pins which should have 0.

Is this PCM internally shorted or otherwise damaged somehow?

I don't understand where this 2.5V is coming from.

This system all worked fine for a thousand miles or so.
 

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Discussion Starter #2
Really I guess what I need to know is whether 2.5V at pins 7&8 with KOEO is indicative of a problem of if i should be looking elsewhere. .
 

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Hey I know this is a long shot but I am having the exact same problem with my ford with a 12 valve same year and exact same voltage in the pins. Did you get yours fixed? I tried a new ecm and that wasn't the problem. My tach hasn't worked since I did the swap
 

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That information he got is probably wrong. It sounds like he was reading the bias voltage in the circuit.

How many wires is the sensor? Two or three?
 

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It's a 2 wire sensor. It's the factory ford cam sensor. When I probe the pins on the harness side there is suppose to be no voltage according to the pin point test that ford has for that p0341 code. And I'm seeing 2.5 volts on both pins. So when I probe pin 7 and 8 I see the same voltage there with the engine pcm bulk head disconnected off the pcm. My tach won't work. This is so frustrating. Everything worked before I pulled the blown engine out of it.
 

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That's just a bias voltage, it's not a problem, that pin point thingy is wrong. Back probe both wires at the pcm, switch the meter to ac voltage and crank the truck. You should see around .8 volts ac.
 

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Oh wait. You see voltage there with the pcm disconnected? That's weird. We'll come back to that later I guess. First check for a signal.
 

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Yes there is less then 1 volt ac during cranking. The pcm has two bulk head connectors when your facing the pcm I left the left one hooked up and unhooked the engine wiring harness. Then put one lead off the meter on pin 7 which is cmp + and put the negative lead of the meter on the ground of the battery and I'm seeing 2.5 volts. And I did the exact same thing with pin 8. Which is cmp -. I don't quit understand the bias voltage thing. According to v 4 if there's any voltage present there is short to voltage? Maybe I'm misunderstanding the pin point test
 

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When I did the crank test to measure the ac voltage of the cam sensor it was unhooked from the cam sensor and I measured that off of the sensor itself, and for the v 4 test. The connector off the pcm was unhooked for the engine harness, and there is no voltage off of the cmp pins. But I'm getting the voltage at pin 7 and 8 directly off the pins off the pcm.
 

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Okay, you unhooked the pcm connector and measured off the pins directly in the pcm?

That's wrong, that's why you were getting the bias. Hook everything back up, back probe the pins in the back of the connector and measure there for ac volts while cranking the engine. Just slide the pins in between the wire and rubber grommet and push it down until it stops. Then hook the meter to the pins with alligator clips.
 

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This check will see if the signal is making it all the way to the pcm or not. Make sense? You're basically checking the wires and sensor. Though we already know the sensor is good, because you already measured that and it was making a signal. Now you gotta see if the signal is making it to the pcm or not.

Disregard the small DC voltage in that circuit. That's supposed to be there, the flow chart is wrong, yet again. That's why I never use them, they never help.
 

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Yes makes sense. I did what you ask and yes there is .8 volts there during cranking. So I started it up and at idle there is .5 volts and when you rev the engine up it can go up to 1.1 volts. Seemed to be working good. Voltage would go up as engine speed goes up. You familiar with diesel conversion specialists kits?
 

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Yes makes sense. I did what you ask and yes there is .8 volts there during cranking. So I started it up and at idle there is .5 volts and when you rev the engine up it can go up to 1.1 volts. Seemed to be working good. Voltage would go up as engine speed goes up. You familiar with diesel conversion specialists kits?
No sir I'm not. Don't really know whats involved in doing something like this. What we know is the pcm is getting a signal, though the signal is strange. The voltage should not be higher while cranking than it is running. It's strange that it runs at all without a cmp input. Which it does have, it just doesn't think it does. So now I'm a little confused. Did you pull that code from the cluster module or the pcm?

So how does this work. You keep the Ford pcm and put the Ford sensors into the Cummins? Or are both pcms used or???
 

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On a side note, which company did you use for your conversion part and wiring? Anything you would do different now? I am getting ready to put a common rail into an excursion.
 
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