I went to start my 2015 LEAF SL a few days ago and got the error message "T/M System Malfunction". The car would not start or allow me to put in into gear.
I feared that there was something major wrong with the transmission.
Thanks to this forum I leaned that this message is often seen, when the 12 V battery voltage is low, which usually happens when the battery is failing.
Sure enough, my battery (only 3 years old and lives in a mild climate) was only charged to 8.3 volts, which is apparently low enough to totally confuse the computer systems in the car and produce a bogus error message.. Removing the battery, charging it up to 12 volts, and replacing it allowed the car to start normally. Replacing the battery with a new one appears to have completely fixed the problem.
Note that this all happened, while I waited for Nissan Service to call me back. They finally did call back about 8 hours after I had called and requested a call back. The initial Nissan Service person that I talked to suggested that I might be able to jump start the car. This is typical of the things I hear from Nissan Service about my LEAF.