Gs 450h Check Hybrid System glitch?

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Hi everyone, I bought a 2008 Lexus GS450h from a guy who owns the car for years, I took the car with no light on dashboard or problem, after driving for like 15 miles check system engine red triangle light came on, on the way home, I called the guy and he told me to continue driving and later check the tyre pressure and that it should be fine. I have checked the tyre pressure which was not even on the tyres, one was 28,32,37 and 30, I inflated all the 4 tyres for 35psi and still the light is on.. Any idea what I can do to correct it as I have plan to have it checked..