I would test voltage at the starter first. Make sure your battery terminal leads are solid.
You can also perform an IPDM test.

As follows:
1) Stand your wipers up so they won't scratch

2) Close hood

3) Open left hand/driver door.

4) Turn IGNITION OFF

5) Turn IGNITION ON

6) Within 20 seconds push door switch 10 times and turn IGNITION OFF.

7) Within 10 seconds turn IGNITION ON and leave ON.

this will test all relays and fuses on your ipdm

 

I would test voltage at the starter first. Make sure your battery terminal leads are solid.
You can also perform an IPDM test.

As follows:
1) Stand your wipers up so they won't scratch

2) Close hood

3) Open left hand/driver door.

4) Turn IGNITION OFF

5) Turn IGNITION ON

6) Within 20 seconds push door switch 10 times and turn IGNITION OFF.

7) Within 10 seconds turn IGNITION ON and leave ON.

this will test all relays and fuses on your ipdm

What does it mean if you do the test as shown but nothing happen? I've done it 3 times with no results.

 

What happens if one of the systems fails the test?

 

Then you need to check the relay(s) and fuse(s) of said fail(failed) part(s). If they’re good, then you’re IPDM would be the indicator of fault.

 

you got some codes delivered by flashing lights or something? what codes did it give you?

here is the manual to help with your trouble shooting. someone recently replaced their ipdm with the new black one and it did fix their troubles so i bet you can find the tests in the manual and decide if you need that part, or not.

this is the post talking about the new ipdm. Ipdm | Nissan Titan Forum (titantalk.com)

here is the manual
Nissan Service Manuals - NICOclub

 

I mean how do I know if something has failed the test? Does the sequence just stop?

One of the issues I'm having with trying to solve the starting problem is that it's extremely intermittent, sometimes it might happen a few times a week, or it might go 8 months without doing it. For example, it hasn't happened since I created this discussion. That's why I figured I'd just replace the IPDM (pretty cheap, comparatively) and if that's not it I won't feel too sad about it.

 

Before you replace the IPDM, try cleaning and perhaps replacing your battery terminal connectors. They are cheap and easy to replace, and have solved more than one person's intermittent no-start issue. You can buy the replacements at O'Reilly or any reputable parts store. They'll run about $15-20 apiece, I think. Maybe as much as $25.

 

I did that and got it to do the self test. The ac clutch is clicking in and out but still won't come on and the obd2 port still isn't working. Any suggestions