Code P0776 Pressure Control Solenoid 'B' control location?

I would check the transmission fluid level which can cause this code. The code P0776 for a 2004 Toyota Landcruiser is associated with a problem in the transmission pressure control solenoid 'B'.

Here is a guide to help and instructions for your car in the images below:

https://www.2carpros.com/articles/how-to-check-and-add-transmission-fluid

Fluid Types
Recommended type: .................... Toyota Genuine ATF WS

Change Automatic Transmission Fluid Only As Necessary.

Generally, it is necessary to change automatic transmission fluid only if your vehicle is driven under one of the Special Operating Conditions listed under "Determining the Proper Maintenance Interval".

When changing the automatic transmission fluid, use only "Toyota Genuine ATF WS" to aid in ensuring optimum transmission performance.

Notice: Using automatic transmission fluid other than "Toyota Genuine ATF WS" may cause deterioration in shift quality, locking up of your transmission accompanied by vibration, and ultimately, damage to the automatic transmission of your vehicle.

Capacities
Fluid capacity (drain and refill): .................... Up to 3.0 L (3.2 qt., 2.6 Imp. qt.)

If the fluid level is okay here is how to change out the pressure regulating control solenoid which is part of the valve body. You can get a rebuilt unit by searching google or ebay. Check out the images (below). Please upload pictures or videos of the problem so we can see what's going on.

Yep, here you go:

X=line pressure solenoid (SLT)

Check out the images (below). Let us know if you need anything else.