If an automatic transmission malfunction is detected, check the ATF level first (see chapter Ongoing care and maintenance). If the level is insufficient, check the condition of the respective oil seals. Carefully inspect all ATF path hoses, as well as the transmission fluid cooler, and make sure there are no signs of leaks developing. The only thing that can still be done by the vehicle owner is to check / replace the information sensors of the AT control system - before proceeding with the replacement of the suspected sensor, poll the control module memory - all any significant failures are recorded in the module memory in the form DTC codes, and in especially serious cases, the TCM automatically switches the AT emergency mode of operation. DTCs are read using special diagnostic equipment connected to the on-board self-diagnosis system connector (DTC) (see chapter Engine Electrical Systems). In the absence of access to the necessary devices, it will be enough to try to at least qualitatively determine the nature of the failure (level: electrical/mechanical) in order to facilitate communication with car service specialists. You should not prematurely start removing AT, since its diagnosis seems possible only in the established position.