[Jmob]

I’d like to remove the 3rd row seats and I’ve watched a few videos. I’m comfortable unbolting things and figure out the mechanical components. That looks pretty straightforward. But, there are wires going to the 3rd row seats. I’m guessing they connect to some sensors. Maybe sensors for “did you forget a kid back there?”

Any experience, advice or warnings related to removal of 3rd row in a 2023 would be appreciated. I’m specifically wanting to know about the wiring harnesses that appear to be attached to the seats and I’m wondering what they connect to.

I’ve watched several videos about removing the 2nd row and getting a dongle for the 2nd row airbags. But I haven’t read any posts or seen any videos with advice or tips indicating if I need a similar dongle to override a 3rd row sensor.

Thanks in advance to anyone with tips re: wiring & sensors on 3rd row removal.

 

[PetTaxi]

No problem with sensors removing third row in my 2021 xse

 

[Chubbysumo]

third row sensors are just seat weight and position sensors. no airbags to unplug, and they should not trigger any warnings on the dash. Just make sure to disconnect the 12v battery for at least 5 minutes before you unplug them, so as to not trigger the computer to have issues.

 

[Jmob]

No problem with sensors removing third row in my 2021 xse

Thanks!! I'm going to give it a shot this weekend!

 

[Jmob]

third row sensors are just seat weight and position sensors. no airbags to unplug, and they should not trigger any warnings on the dash. Just make sure to disconnect the 12v battery for at least 5 minutes before you unplug them, so as to not trigger the computer to have issues.

Thanks for the info on what the sensors do. I'll give it a shot and see what happens

 

[Jmob]

third row sensors are just seat weight and position sensors. no airbags to unplug, and they should not trigger any warnings on the dash. Just make sure to disconnect the 12v battery for at least 5 minutes before you unplug them, so as to not trigger the computer to have issues.

this may be a dumb question, but when you say, "unplug the 12V battery for at least 5 min" do you mean the main car battery under the hood? Or is there a separate 12v battery? This is my first hybrid and I obviously have no idea what I'm doing.

 

[Sienna9816]

There's a 12V battery behind 3rd row passenger in the sidewall.

(Just follow the kind of loud buzzing noise back there, and you've found it . This fan makes it presence known a little bit too often.)



This is for future reference. This is not needed now since you will be disconnecting the battery.

Don't run your car in ACC mode for more than 10 minutes. It will drain 12V battery quick. If you're doing something inside car too long, keep it in Ready mode i.e. push start with brake pedal depressed.

 

[pamhar]

There's a 12V battery behind 3rd row passenger in the sidewall.

(Just follow the kind of loud buzzing noise back there, and you've found it . This fan makes it presence known a little bit too often.)



This is for future reference. This is not needed now since you will be disconnecting the battery.

Don't run your car in ACC mode for more than 10 minutes. It will drain 12V battery quick. If you're doing something inside car too long, keep it in Ready mode i.e. push start with brake pedal depressed.

Should be part of some sticky on what not to do with a hybrid Sienna.

Can add leaving sliding doors open too long and what to do if did... don't top off fuel after pump stops... take hvac out of ECO if not happy with results... correct way to boost... etc.

 

[Jmob]

Wow. Thanks for the tips about "ready mode" vs ACC mode. Years ago when we had a 2000 Honda Odyssey van, we left the doors open for hours while we slowly loaded a bunch of stuff for a long trip. The interior lights never went off and it drained the battery. I guess this is the same concept.

@Sienna9816 -- what is the "correct way to boost" ?

Thanks for all the tips!!! btw. I'm still exploring all the menus and buttons.

The first thing I changed after a week of driving was the lane assist settings. It was super aggressive when I first got the van. I found a sensitivity setting for it and took it off "center seeking" (or something like that). Now the lane assist doesn't feel like it's trying to drive me into another lane, or off the road.

 

[Chubbysumo]

if you want to leave the doors open for extended periods of time without issues to the 12v battery, turn off the powered doors and open them manually, and then turn off the interior lights with the switch by the roof console.

 

[Sienna9816]

Wow. Thanks for the tips about "ready mode" vs ACC mode. Years ago when we had a 2000 Honda Odyssey van, we left the doors open for hours while we slowly loaded a bunch of stuff for a long trip. The interior lights never went off and it drained the battery. I guess this is the same concept.

@Sienna9816 -- what is the "correct way to boost" ?

Thanks for all the tips!!! btw. I'm still exploring all the menus and buttons.

The first thing I changed after a week of driving was the lane assist settings. It was super aggressive when I first got the van. I found a sensitivity setting for it and took it off "center seeking" (or something like that). Now the lane assist doesn't feel like it's trying to drive me into another lane, or off the road.

Jump Starting / Battery Charging ECU Damage Warning

Just a public service message from your Admin Team about possible ECU damage from using jumper cables, jump packs and possibly even battery chargers. Apparently if the existing rear mounted 12v battery in your hybrid is in a very low state of charge, it's service as a capacitor to absorb spikes...

www.siennachat.com

See above.


If you get "parking brake unavailable" message, that is a tell-tell sign of a drained battery.

Before trying above, lock everything and sit for 10-15 minutes and try again. It may start without a boost.

 

[DKH]

if you want to leave the doors open for extended periods of time without issues to the 12v battery, turn off the powered doors and open them manually, and then turn off the interior lights with the switch by the roof console.

Or replace all your interior bulbs with LED which use way less power.
Way too many dead batteries in my past with interior lights being left on

 

[Chubbysumo]

Or replace all your interior bulbs with LED which use way less power.
Way too many dead batteries in my past with interior lights being left on

those little bulbs use maybe 2 to 3w each anyways, so you switching down to an LED thats gonna use 1w isn't gonna make all that much difference(6 bulbs going from 18w total to 6w). turning off the door power, however, will disable the kick sensor, thus, it lets the BCM sleep, and stop using lots of power.

 

[weimeier]

Any one successful removed 2nd row and 3rd row seats on a 2023 sienna here? My question is 1, if all of them can be removed? 2, when 3rd row seats removed, is it one big piece or two separate 60/40 2 pieces?

 

[Chubbysumo]

2nd row seats are easy to remove, its just 4 bolts for each seat. the sliders will not come out, you have to remove the fuel tank to actually remove the bolt that holds it down to the floor. you will need a 3 to 3.5ohm resistor for the airbag bypass, and you will have to disconnect the 12v battery while you do it, otherwise you will need to take it to a dealer for a reset. The rear seats only have seat belt and weight sensors, so they won't trigger any dash lights by removing them.

 

[weimeier]

2nd row seats are easy to remove, its just 4 bolts for each seat. the sliders will not come out, you have to remove the fuel tank to actually remove the bolt that holds it down to the floor. you will need a 3 to 3.5ohm resistor for the airbag bypass, and you will have to disconnect the 12v battery while you do it, otherwise you will need to take it to a dealer for a reset. The rear seats only have seat belt and weight sensors, so they won't trigger any dash lights by removing them.

Is the 3rd row seat one complete piece, or 2 separate piece?
Thanks

 

[Sienna9816]

Is the 3rd row seat one complete piece, or 2 separate piece?
Thanks

2 piece - 60/40.