Hey @Jasim Khumi, your model of Pajero is not likely to have heating issues like the new ones as far as your car is well maintained and serviced.
The OBD scanner is a good idea to monitor but Pajero does not have a lot of sensors e.g you will get the actual coolant temperature but not ATF temperature....
For summer, i would recommend to:
1. change your coolant fluid if it has not been changed in a while.
2. get the Air Conditioning System checked and topped up the AC Gas if required as you will need your Air Conditioning more
3. keep a good eye on the Tyres regularly because it will be exposed to higher temperature and stress as well.
Lastly, as usual keep monitoring your gauges when driving.