Me again... I dropped the pan last weekend and tested all the solenoids in there. There are 3 identical PWM shift solenoids, 2 identical ON/OFF shift solenoids and 1 EPC solenoid. One of the ON/OFF solenoid has open circuit. The coil must have been busted.
I ordered that part from
www.transmissionpartusa.com for $26. I called one of the dealer here and they quoted me $90 for it.
I hope this would fix my problem. Thanks...