2010 Nissan Frontier pro-4x package. 4wd will not engage. Using the flash codes pulled codes 3,6,10,11, and 13. No idea where to even begin diagnosing.

SOURCE: 1999 isuzu rodeo 4wd not woking

I had this happen to a 1999 4x4 LS and my sisters boyfriend mentioned to periodically turn 4x4 on/off at least once a month.
What I did was go down a stretch of road slowly and attempt to turn it on/off till it became unstuck.
Drove around 10 miles on a road that was hardly used...to get the stupid light to quit flashing I had to put it in park and try to creep forward ---while using off settiing or put in park then reverse...while using the off -setting on 4x4. My patience paid off. They get sticky...you must be cautious... because there is a way to cause vibration and then it won't start...some deadman feature that I experienced once and the LWD must have slipped in a little and I had to look at everything.
Mine is an Automatic with the shift on the floor...that can get sticky too.

Good luck and hope this helps...mine had lots of growing pains but I get 23 mpg and it runs/idles better and the only gremlin left is some short in the dash which leaves the lights D/3 (one or both on)for the shift indicator on:)

SOURCE: 4 WHEEL DRIVE DONT WORK

first off your heater dial swithc is buggered. and as for the four wheel drive is it all electric diff locks or do you have to get out and lock hubs in etc?

SOURCE: 2004 Mitsubishi Montero Sport AWD engaging 4WD High

It's either the sensor on the top of the transfer case, or the one on the front diff. Look here, scroll down to about the third post.

http://msport97.proboards.com/index.cgi?board=faq&action=display&thread=6258

SOURCE: engine repair code P0325

po325--ignition system or missfire.

SOURCE: 1999 Frontier: nissan frontier 2000 automatique tansmision revers...

Either transmission oil pump is on its way out or reverse circuit is clogged , reverse shift solenoid is defective TCM may be defective , transmission range sensor begining to fail or manual shift valve and pressure regulator are defective.

Suggest taking the vehicle to a transmission repair shop they will diagnosis it and repair it.