Horse,
there are 2 common codes associated with this cam and crank sensor
E-27 which is a crankshaft sensor signal phase error
E-28 which is a camshaft sensor signal phase error
both work in common with each other and if either signal goes out of range from what the ECM expects to see from either sensor it will cause MIL light to light and code to display.

At first when the code first comes in there will be an immediate engine (limp mode) set so the engine will not run full speed. (this is something i've seen happen or not happen depending on where the problem is)
Tried to change the sensor related to the code which in this case the E28 would be related to the cam sensor.
Didn't help, code returned, even tried replacing the crank sensor, still no joy, code still returned.
Finally wound up checking the coils for any broken wires or other problems, none found, then last resort pulled the plugs and found a very wide gap so plugs were changed.
Problem solved, code went away and the truck ran perfect.
I have seen either sensor cause this problem, also have seen broken wires on any one of the coils cause this too. But the most common issue i found to throw either code was a spark plug or coil failure.

What causes the codes to set is the ECM seeing the signal from either sensor going out of range more than it can compensate for.
As spark plugs wear or coil pack fails it causes the timing dwell to change, ECM will compensate for this to a point, if plug gap increases too much or coil pack completely fails? ECM sees this variance as too wide and expected signal goes out of expected range and sets one of the 2 codes depending on which component fails.

Troubleshooting either code can be troublesome especially if you do not have a GSM diagnostic tool or the laptop program to monitor the signals. So without these it basically turns into a guessing game even with the troubleshooting information from the manual. And the funny part of it is the troubleshooting information does not even mention the spark plugs as being a potential cause, it always refers you toward the sensors or coil packs which is where most guys make that mistake.

And word to the wise, if you ever do wind up replacing any ignition component be it a cam sensor or crank sensor or spark plugs do not use aftermarket parts, use only OEM parts from mitsubitshi/cat. 90% of the time when i tried using aftermarket parts i always had to go back and deal with it again because of a part failure.

Horse,

I do not know about the code issue but make sure that if you do change the plugs that you use the Nissan original 22401-FU42A or NGK FR2B-D. Nissan went through several versions of this plug changing the heat range and reach.

Have you personally experienced this with the plugs? I had a code 28. Wouldn t run. Replaced the cam sensor. It now runs but the code is still flashing. I did notice a slight spark plug ignition miss. I m going to do the pedal dance & try to clear & see if that takes care of it. What bothers me is that I read in the s manual the the codes are suppose to clear by them selves when running normal.

how long since tuneup? has it ever been tuned up?
check the spark plugs
this is a known issue causing this code
rarely is it the sensor, i wouldn't rule it out totally but generally its been bad plugs from my experience

good luck

Ken n;
The fault code is the camshaft's position sensor "circuit" has a problem.
At start up no camshaft position (phase) signal has been detected and decoded for more then a predetermined period of time at the Engine Control Manager (ECM).
The camshaft position sensor signal is not been detected for a predetermined time period during engine running. (during crankshaft position signal input)
The camshaft's position sensor signal's waveform isn't detected for a predetermined period of time during engine running. (crankshaft position sensor signal is detected at the ECM)