B1821: Open side airbag (squib) circuit, driver seat side (Toyota)

Open in side squib circuit, driver seat

Severity: Inspect soon

An open side squib circuit means the side airbag may not fire, and the code turns the SRS light on.

Safety-critical system: explanation only, no DIY steps. Source: how we rate severity

B1821 in short

On Toyota, B1821 means the airbag computer sees an open circuit to the driver-side seat side airbag. Toyota has linked it to terminal crimping on the Sienna and owners found a pinched seat connector on a Camry. That side airbag may not deploy, so have it checked soon and leave the wiring to a technician.

A squib is the small igniter that fires an airbag. The SRS computer checks each squib circuit. If it finds an open, it stores a code and lights the SRS lamp.

Toyota repair manual supplement EL002-08 for the Camry Solara calls B1821 and B1826 an open side squib circuit, and a 2025 complaint quotes a mechanic reading B1821 as an open in the driver seat side squib circuit.

Toyota bulletin 0172-12 improved terminal crimping on the side airbag for the 2011-2012 Sienna, and a 2006 Camry owner quoted a dealer finding that a loose seat track covering pressed on the airbag connector under the seat. Both point to the seat connections.

Pick your make

B1821 is a manufacturer-specific code: its meaning depends on who built the car.

Other makes: meaning not verified. Check with a scan tool that reads manufacturer definitions.

B1821 on Toyota

Most likely causes

Cause 1: Poor terminal crimp at the side airbag connector
Supported by vehicle data
Why it ranks here
Toyota bulletin TSB-0172-12 improves terminal crimping of the side airbag on 2011-2012 Sienna for B1821 and B1826. Only the summary was read.
What would change this
Rises on a Sienna of those years with an intermittent lamp. Falls on other models.
Cause 2: Seat connector pushed or disturbed under the seat
Supported by vehicle data
Why it ranks here
A 2006 Camry dealer finding quoted in a complaint was a seat track covering pushing on the airbag connector, giving no communication at the squib connector.
What would change this
Rises if the lamp changes when the seat is moved.
Cause 3: Side airbag wiring assembly
Supported by vehicle data
Why it ranks here
A Prius owner was told by the dealer that the wiring assembly may need replacing on one or both sides for B1821.
What would change this
Rises if connectors are sound and the open persists.

What to test first

Start at step 1. Each result tells you what it means and where to go next.

Step 1: Have the airbag or body codes read with a scan tool and note the exact code and any others.
Low riskTool: scan tool with module access
- IfB1821 with B1826 on a Camry or Solara
  It meansToyota calls this an open side squib circuit.
  Go to step 3
- IfIntermittent B1821 on a 2011-2012 Sienna
  It meansTerminal crimping is the bulletin cause.
  Points to: Poor terminal crimp at the side airbag connector
- IfLamp changes after moving the seat
  It meansThe seat connector is suspect.
  Points to: Seat connector pushed or disturbed under the seat
- IfAny other combination
  It meansCheck bulletins next.
  Go to step 2
Step 2: Give your VIN to a dealer and ask for any bulletin or recall on the system.
Low risk
- IfA bulletin applies
  It meansThe dealer follows it.
  Go to step 3
- IfNothing applies
  It meansThe service manual diagnosis is next.
  Go to step 3
Step 3: Have a trained technician diagnose the side squib circuit, starting with the connectors under the driver seat.
Best left to a shopTool: maker's diagnostic tool and service information
Warning:Never probe airbag connectors or wiring with a test light or meter, and never unplug them yourself. Airbags and pretensioners can still fire with the ignition off. Leave this to a dealer or trained technician.
- IfConnector or terminal fault found
  It meansRepair or replace the terminal or connector.
  Points to: Poor terminal crimp at the side airbag connector
- IfWiring fault found
  It meansReplace the wiring assembly.
  Points to: Side airbag wiring assembly

Symptoms

SRS or airbag light stays on
SRS light comes and goes

How to fix

This is a safety-critical system, so we explain the code but don't give repair steps. Have it inspected by a qualified technician.

Parts and cost context

Side airbag connector and wiring:A 2006 Prius owner was quoted the wiring assembly. Airbag parts must be handled by a trained technician. Labour varies; get a quote.

Labor varies by vehicle and shop; get a quote before you approve a repair.

Compare used part prices on PartPriceGuide

On your vehicle

Toyota

2004–2008 · Camry Solara
Supported by vehicle data
Toyota repair manual supplement describes B1821 and B1826 as an open side squib circuit. Whether it is still current is not verified.
2011–2012 · Sienna
Supported by vehicle data
Toyota improved terminal crimping of the side airbag for B1821 and B1826. Whether the bulletin is still current is not verified.
2004–2006 · Camry
Supported by vehicle data
Owner complaints quote B1821 as an open in the driver seat side squib circuit and a pinched seat connector.
2006 · Prius
Supported by vehicle data
An owner complaint quotes a dealer saying B1821 needs the side airbag wiring assembly replaced.

EL002-08Status unverified
Toyota repair manual supplement for SRS light with B1821 or B1826 open side squib circuit
2004–2008camry-solara · NHTSA 10024310
2004-2008 Camry Solara. Summary says open side squib circuit; updated May 2008.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.
TSB-0172-12Status unverified
Toyota Sienna intermittent SRS light with B1821 and/or B1826, side airbag terminal crimping improvement
2011–2012sienna · NHTSA 10047943
2011-2012 Sienna. The fix improves terminal crimping on the side airbag.
We couldn't confirm whether this bulletin is still current, so it doesn't count as confirmation.

No curated relationships for B1821 yet.

All Airbags and seat-belt restraints (SRS) codes

Sources and review

Toyota EL002-08: Toyota repair manual supplement for SRS light with B1821 or B1826 open side squib circuit — NHTSA (manufacturer communication)
Toyota TSB-0172-12: Toyota Sienna intermittent SRS light with B1821 and/or B1826, side airbag terminal crimping improvement — NHTSA (manufacturer communication)
NHTSA complaint ODI 11654816: Toyota Camry 2004 — NHTSA (owner complaint)
NHTSA complaint ODI 10578584: Toyota Camry 2006 — NHTSA (owner complaint)
NHTSA complaint ODI 10504057: Toyota Prius 2006 — NHTSA (owner complaint)

Last reviewed: October 16, 2026
Written by: Saurabh K.
Editorial review: Pending
Technician review: Technician review pending

This page explains what a code usually means; it is not a substitute for a professional inspection. How we source and review · Report an error

Severity: Inspect soon

Pick your make

Most likely causes

Cause 1: Poor terminal crimp at the side airbag connector

Cause 2: Seat connector pushed or disturbed under the seat

Cause 3: Side airbag wiring assembly

What to test first

Step 1: Have the airbag or body codes read with a scan tool and note the exact code and any others.

Step 2: Give your VIN to a dealer and ask for any bulletin or recall on the system.

Step 3: Have a trained technician diagnose the side squib circuit, starting with the connectors under the driver seat.