Enters snail mode, needs 12v disconnect to fix.

[2016nz30kwh]

Hello,

I own a 2016 Nissan Leaf with a 30 kWh battery and a State of Health (SOH) at 70%. Recently, I've encountered an issue where the car enters a reduced power mode, despite the main battery having ample charge. Additionally, after coming to a stop, it refuses to switch back to drive mode.

A temporary solution I've found is to disconnect the 12v battery for a minute. After reconnecting it, the car resumes normal operation and drives properly.

This problem first emerged six months ago and has been occurring with increasing frequency, totaling six instances so far.

Initially, the vehicle was sent to a service center where it remained for several days. Upon return, the only feedback received was that the computer system had been "reset." I've scheduled another appointment to diagnose the problem and review any error codes.

I installed a new 12 volt battery after the first time this happend.

Could anyone provide insights or suggest a starting point for troubleshooting this issue?

Thank you.

 

[cornbinder89]

You are likely getting an interlock code for some reason, Disconnecting the battery clears the code temporarily until the condition shows it self again. Turtle and not being able to go back into drive are symptoms, not the root cause. A discharged 12 volt CAN cause this as well but I doubt that is what is at the root of the problem, and you replaced the 12 volt and still have the problem.
You are going to need to get a code scanner that will work on the Leaf to see what DTC's are present when the problem occurs.
If it were just going in to turtle, I would guess a bad cell or more in the battery (without being able to see without a scanner or Leafspy) but being locked out of drive suggests a more serious code is being set, like a HV isolation issue or something (and there is quite a list) that the VCM deems serious enough a failure, so it prevents the car from being driven.
There are so many things that the scan of the DTCs are the only way to point you in the direction to look.
Many generic code readers don't work with the LEAF as the LEAF doesn't have an engine or "emissions system" so not technically a OBD 2 system, even though it does have an OBD2 port to plug into.

 

[2016nz30kwh]

You are likely getting an interlock code for some reason, Disconnecting the battery clears the code temporarily until the condition shows it self again. Turtle and not being able to go back into drive are symptoms, not the root cause. A discharged 12 volt CAN cause this as well but I doubt that is what is at the root of the problem, and you replaced the 12 volt and still have the problem.
You are going to need to get a code scanner that will work on the Leaf to see what DTC's are present when the problem occurs.
If it were just going in to turtle, I would guess a bad cell or more in the battery (without being able to see without a scanner or Leafspy) but being locked out of drive suggests a more serious code is being set, like a HV isolation issue or something (and there is quite a list) that the VCM deems serious enough a failure, so it prevents the car from being driven.
There are so many things that the scan of the DTCs are the only way to point you in the direction to look.
Many generic code readers don't work with the LEAF as the LEAF doesn't have an engine or "emissions system" so not technically a OBD 2 system, even though it does have an OBD2 port to plug into.

Thanks, hopefully the local Nissan service centre can scan the DTC's.
The last time the technicians didn't give any clue to what might be wrong, they just sent the car back after a reset.

 

[cornbinder89]

I haven't had to take my Leaf in to Nissan yet, but them not having a clue seams to be normal from what I hear. It is vastly different than their ICE cars and really needs someone trained in just the EV's , Most dealer techs are supposed to know the whole line-up but that doesn't mean they do.

 

[2016nz30kwh]

The car went in for a service with Nissan today.

The only DTC reported is:
P33913 cell overcharge module.

They found one of the 12 volt battery terminals was not tight enough. They suspect that is the cause.

Hopefully it is that simple, time will tell!