What to check with OBD2.

What programs do you use for OBDII?

 

Okay. Do you have an Android or an iPhone?
Maybe a laptop with a special cable?

For Android you can use Torque, Dr. Prius, Hybrid Assistant.

 

Not all OBDII scanners work equally well with different cars. For Toyota, Techsrteam is recommended.

 

There are options
A. You connect your scanner and it does not damage the car, but it does not give you the correct information
B. You connect your scanner and it damages the car, because it is not designed for its use.
C. You connect the scanner and it does not damage the car and gives you the correct information and the correct codes.

 

Are there any signs of malfunction on the car you are buying?
Is the check engine light on?
Is the red death triangle on?
Are other error indicators red or yellow?

 

A high-voltage battery cannot be checked with a regular scanner. The check is good in dynamics, when the battery is discharged and charged, the parameters, voltage, current and internal resistance of the modules are monitored.
An error in the ABS unit is serious. This can affect the safety of the brake system. And of course, the costs of restoring the work, spare parts.
There is a method for reading errors with a simple paper clip. In the OBDII connector, short-circuit pin 4 and pin 13.

 

The problem with the gas tank is that it is not disassemblable. The fuel pump and fuel filter are inside and cannot be changed.

 

How much is the car worth now?
How much do you expect to sell it for when you stop using it?
How much do you expect to drive it in a year, in two?
How much to spend on repairs?
How much.... Many unknowns.
The Prius is economical. You can find many good parts at junkyards for next to nothing.
But any car ages over time, requiring additional investment.

Instrumental?

I don't know.

Unscrew the trough with the wiper motor, unscrew the spark plugs and look at the condition of the cylinders. Visually!
On the Prius GEN2, the engine often eats oil, but not coolant.

 

I have not used such devices, so I can not reliably say about this possibility.
The cooling system has many components. Engine, radiator, heater in the cabin, thermos for keeping hot coolant, pumps, taps, hoses. Where to connect the device?