I've tried re-setting the ECU by disconnecting the negative terminal of the battery for more than 5 mins., pero the D4 light is still blinking.

Pero before, when this blinked, I just turned off the engine tapos after starting it after 5 mins, di na sya nagbi-blink. Occasionally there were times na after driving for 10 mins, blink ulit. The problem was intermittent, there were days na meron, sometimes wala. For the whole month of July, di nag-blink.

But now, right after starting the engine, blink agad. Siguro pa-check ko muna sa Zee sa Aurora, kesa bumili ako agad ng surplus na tranny