iamchemist
Posts: 57
Joined: Fri Mar 18, 2011 12:51 pm
Delivery Date: 20 Jan 2012
Leaf Number: 017449
Location: Wilmington, NC

T/M System Malfunction

Thu Dec 06, 2018 9:48 am

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.

User avatar
mwalsh
Posts: 9557
Joined: Thu Apr 22, 2010 10:10 am
Delivery Date: 05 Jan 2011
Leaf Number: 0213
Location: Garden Grove, CA

Re: T/M System Malfunction

Thu Dec 06, 2018 10:44 am

Which is why this forum is worth it's weight in whatever you value the most. :D
2011 Blue Ocean SL with 77,000 miles
2015 pack on 12/30/15
Tinted windows
Bridgestone Ecopia 422+ tires
L1 EVSE upgrade
FIAMM horns
Superbright LED lighting
2013 sun visors
LED shifter
Heated seats
GT-R map lamp lenses
Altima illuminated door switches

Levenkay
Gold Member
Posts: 496
Joined: Mon Sep 26, 2011 10:01 pm
Delivery Date: 11 Aug 2018
Leaf Number: 308382
Location: Portland, OR

Re: T/M System Malfunction

Thu Dec 06, 2018 12:05 pm

iamchemist wrote: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..

Yeah; bummer. See, most microcomputer systems need something like 3.3V to operate, and while it may someday be possible to derive 3.3V from a raw supply that's fallen from 12V to 8V, it's not reasonable to expect Nissan to pull a miracle like that off just now. And besides; those computers probably need a dozen milliamperes or more to run; not the sort of punch that you could reasonably expect from a battery that's only intended to crank a starter motor. Well, maybe you can when it's in tip-top condition, but not one that's been kept on a starvation diet for a few years. Some might wonder whether, on its way down from 12V to 8V, the system computer could find twenty microseconds to record a trouble code signifying, "hey! my misapplied battery's toast!". Dreamers.

Lothsahn
Posts: 94
Joined: Thu Apr 05, 2018 4:35 pm
Delivery Date: 04 Jan 2018
Leaf Number: 007797

Re: T/M System Malfunction

Thu Dec 06, 2018 7:17 pm

Levenkay wrote:Yeah; bummer. See, most microcomputer systems need something like 3.3V to operate, and while it may someday be possible to derive 3.3V from a raw supply that's fallen from 12V to 8V, it's not reasonable to expect Nissan to pull a miracle like that off just now. And besides; those computers probably need a dozen milliamperes or more to run; not the sort of punch that you could reasonably expect from a battery that's only intended to crank a starter motor. Well, maybe you can when it's in tip-top condition, but not one that's been kept on a starvation diet for a few years. Some might wonder whether, on its way down from 12V to 8V, the system computer could find twenty microseconds to record a trouble code signifying, "hey! my misapplied battery's toast!". Dreamers.


That post is sarcastic gold. Thanks for making my day.

Add to it: It's also a shame that there's no way to remove the 12v battery entirely. If only there were a large battery of sufficient power, we could avoid the lead acid one entirely...
2011 Silver SV, purchased 2018, lives in Missouri (previously in CA)
LeafSpy Pro + BAFX Products OBDII dongle
7 bars and really feeling the range squeeze

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