What is error code code p1138 for Nissan Sentra?

on intake manifold

Can you diagnose your own vehicle?

Then you need to go to someone that can

You should not be using it, no matter what
research you do,as you have a check light on & as
you said, don't have a definite diagnoses.

A TPS Sensor will cause several problems, but not likely
to the point it would die.

Explain the #39---then stop with that

https://www.obd-codes.com/p0450

swirl control valve

Its telling you that you have a recommended service coming up at 30K miles. The dealer will reset the light when you bring the car in. Nissan recommends you to do your maintence's every 7500 miles. A 30K service will consist of an oil change, change air filter, coolant flush, replace PCV valve, in cabin air filter, along with checking many other systems in your vehicle. Hope this helps.

Of coarse you haven't
You only find the Generic OBD Codes, required by the Govt
The dealers took your tax dollars, and now want your vehicle back, so they can take more money
The P Codes and others, are Manufacturer Specific

P1138 --Lack of HO2S Switch,Indicates Lean

Without writing a book on that issue, You may have a bad Oxy Sensor
It is a rather unusual code,so I would have it checked out by a local repair shop.

I SOLVED IT WITHOUT ANY HELP FROM FIXYA.COM
NO THANKS TO YOU FOR ALL THE HELP YOU DID NOT GIVE ME IN FINDING A SOLUTION.

AMF

There was a recall on the Crank Angle Sensor and another recall in which the engine would consume too much oil due to faulty piston rings

buy yourself a scanner [ebay] only cheap & learn to do it yourself with its manual it comes with alist of error codes & their meaning
costs less than the last time!

That is a swirl control valve code. The swirl control valve is on the intake manifold and unfortunately the only way to get the valve is to replace the entire intake assembly, it is not available seperately @ this time. You will have to purchase this and the gasket from you Nissan dealer. Hope this helps.