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R51 changing up gear in manual mode - P1815 M-MODE Switch error code in computer

18K views 6 replies 2 participants last post by  Berto14  
#1 · (Edited)
Hi all,

I have a Nissan Pathfinder R51 2013

A few months ago while on the beach i had my Pathfinder in 4Low and manual mode. The transmission (in manual mode) kept changing up gears at approx 2200-2300 rpm. At the time I figured this was normal and must have been a protection setting (Novice 4wd'er)

On the weekend I did a 2day 4wd course with a professional company in Perth. Using my own vehicle. The first day was in sand and the next in the bush.

The first day was in the sand, I engaged 4wd low and used manual mode. I noticed that the gears would change up automatically at approx 2200-2300 rpm. This would happen while working through soft flat sand and on big inclines.

The second day was in bush terrain.
Again in 4wd low and manual mode when doing climbs under load and in sports mode the Pathfinder would up gear by its self at the revs mentioned above. Although It didn't do it on level ground or downhill, I suspect due to having more traction in this terrain.

I was out with 13 other 4wds and everyone said this is weird behaviour when manual mode is selected.

Anyone else heard of this or had this happen to them? Also what's the best way to attack this issue?

Thanks
Nick
 
#7 ·
Update 9/03/2022

I have sourced a replacement shifter assembly and will look to replace tomorrow

Talked to my local transmission shop and the guy took it for a drive in 2WD and manual mode worked fine (As it previously did) it only happens in 4Low (Cant recall if it happens in 4High)

He was kind enough to check the codes for me and there was none present
 
#4 ·
P1815 is usually caused by one of the M-Mode switch contacts "falsing" and causing the tranny to see two gears at once. On some shifters like older Altimas the microswitches were exposed and could be replaced, but on the R51 it pretty much means a new shifter because the contacts are inside the shaft and pivot assembly.
Image
 
#3 ·
Update 6/03/2022
We initially cleared the P1815 fault code and this seemed to fix the manual mode switch issue.

Took the pathfinder back to the sand dunes to test it out

We tested the vehicle is very soft sand and slight incline and manual mode kept shifting upgear manually at approx 2100rpm

This time recorded on video!

Any help or suggestion on how to fix rhis issue would be great
Thanks