B1926: Left Rear Pretensioner Squib

Circuit fault

What B1926 means

The rear left pretensioner sits in the retractor behind the rear side trim or in the seat back structure. Its igniter is wired back to the airbag control module through the floor harness. B1926 is stored when the module sends its test current down that circuit and gets an open reading rather than the resistance a healthy igniter presents.

Rear circuits are easy to disturb without realizing it. Rear seats come out for subwoofer installs, carpet drying, and accident repair, and the pretensioner connector is often hidden behind a trim panel that gets popped loose and pushed back without the plug ever being checked. A fired pretensioner from a prior wreck reads the same way.

Common causes

• A rear pretensioner that deployed in a previous crash and was not replaced
• The connector behind the rear quarter trim or seat back left unplugged
• Floor harness damage from seat removal, cargo, or water in the rear footwell
• An open igniter inside the rear retractor assembly
• Corrosion at the connector from a leaking rear window seal or trunk seal
• A wire pinched when the rear seat was bolted back down

Crash data or hardware fault?

Live resistance is what this code watches, which is why it lands in the circuit family. The reading changes as the wiring changes, and the code clears itself once the loop is whole. Crash data sits at the other end of the spectrum: one permanent entry written at deployment that stays put until a module reset removes it.

Does our reset clear it?

Resetting the module will not close an open rear pretensioner circuit. Replace a fired retractor or repair the harness, then confirm the loop reads correctly. If the vehicle was in a crash and the module also holds deployment data, mail it to us after the parts are installed and we clear that record so the system can arm again.

Which makes throw it

B1926 appears under Lexus in our lookup, and it only applies to models that build pretensioners into the rear seat belts. Not every chassis has them, so confirm the vehicle is equipped before ordering parts.

What to do next

Pull the rear seat bottom and the lower quarter trim to get eyes on the retractor and its connector, since access is the hard part of this job and everything else follows from seeing the parts. Check whether the belt is locked short and the retractor housing is discolored, which points to a fired unit. With an intact pretensioner, reseat the connector and measure the loop at both ends. We can supply genuine OEM rear seat belt assemblies for Lexus applications. Related codes: B1906, B1941, B1879.