why the indicator light of D4 of A/T will start blinking after while driving.

What is your question?

normally, the indicator D4 light will light up when shift to drive. however, after a few minutes driving, the D4 light will start to blink - on/off mode. Even if I shift the gear to D3 first for initial drive, when car is running, the D4 indicator light will blink as well, while the D3 light remains on.