4th-gen (2021-) Sienna: Removing 2nd-Row Seats

This article is a collection of information and resources for removing the second-row (middle row) seats on the 4th-generation Toyota Sienna (2021-).

The Situation

2nd-row seats of the previous Sienna generation (2011-2020) were easily removable by pulling a latch. However, the 4th-gen Sienna’s 2nd-row seats are not removable by the user, at least according to Toyota. This is in part because there are now SRS airbags inside the backrests, as seen in this crash test video.

Instead of a quick-release mechanism, the 2nd-row seats are now secured with 4 bolts hidden behind plastic trim pieces. Additionally, the seat airbag connector must be disconnected.

The Procedure

This video shows the process for removing the 2nd-row seats, which involves disconnecting the 12V battery to depower the airbags, prying off seat trim, disconnecting the airbag and seat heater/seatbelt connectors, and removing 4 bolts.

These instructions are focused on the captain chairs, but the bench seat has a similar procedure.

Written Instructions

 7-Seat8-Seat
RemovalLeft or RightLeft
Right
InstallationLeft or RightLeft
Right

Tools Used

I’m linking both the bare minimum tool you need just by itself, and alternatively a better value set if you plan on keeping a good set of tools for DIY automotive work.

Minimum neededExpansion set or more versatile upgradePurpose
10mm socket1/4"-drive socket setTo loosen/tighten the battery terminal bolt
1/4"-drive ratchetFlex-head 1/4"-drive ratchetTo drive the 10mm socket
17mm socket1/2"-drive socket setTo loosen/tighten the seat bolts
1/2"-drive socket extension1/2"-drive socket extension setTo reach the recessed seat bolts
1/2"-drive ratchetMore compact 1/2"-drive ratchet if you have a torque wrench and/or impact wrenchTo drive the 17mm socket
Pry toolInterior trim tool kitTo pry off the seat trim
1/2"-drive torque wrenchAdditional 1/4"-drive torque wrench if you don't trust "hand-tight" for battery terminal eitherTo ensure seat bolts are re-tightened to proper torque

The Problem

Once one or more seats are out, if the battery were to be reconnected and the car started, you would see this warning:

The car knows that one or more of its airbags are missing, so it complains. It stays on the gauge cluster screen and also appears on the infotainment screen. Fortunately, it does not beep continuously. Some Toyota dealership employees have claimed that all other airbags stop working in this situation. While this has not been positively verified, it’s wise to err on the side of caution to avoid a “cry wolf” situation where a false positive masks a real, even unrelated airbag problem.

The Solution

You can use an airbag simulator to resolve the airbag warning message and ensure that the SRS airbag system is working normally. I developed one specifically to fit the Sienna’s airbag connector.

You can buy these airbag simulator dongles from my web store or eBay. Get 2 if removing 2 seats.

Related Project

I am working on developing instructions for converting the AWD Siennas’ seats to have the ottoman legrests found on only the FWD versions.

This will involve finding the necessary parts (costing ~$1,300 USD per seat) and figuring out how to retrofit them to the AWD seats. If you’re interested in this conversion, please chip in to this fundraiser.

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Chris Saeger
Chris Saeger
13 days ago

Great work on the dongle. Just curious. Do you think the seats could be reinstalled facing the rear? Thinking that facing rear they could be moved very far forward and the seat could serve as a support to a bed platform.