Try resetting you mfd, let the car warm up first. Turn off engine, push and hold joystick in, turn car on, let go once gtr logo is displayed, straight away push joystick 5 times, should go into diagnostic mode, wait till all sensors turn green, exh temp takes awhile if engine was cold, drive around the block to get all sensors up, then turn off engine and start back up, exh temp should display.