B1693: Right Side Airbag Sensor Initialization

Hardware fault

What B1693 means

This code belongs to the right hand side airbag sensor on Lexus vehicles. When a satellite sensor is installed, the airbag control module has to run an initialization routine so it knows the sensor is present, which variant it is, and what a normal reading from it looks like. B1693 means that routine started and stopped before the module accepted the sensor.

Because the fault describes a setup step rather than a broken part, the sensor itself is often perfectly good. A scan tool that dropped its connection partway through, a battery disconnect during the procedure, or an installer who bolted the sensor in and skipped the step will all leave the module sitting in this state. The light stays on until the routine runs to completion.

Common causes

• A right side sensor replaced without running the initialization routine afterward
• The routine interrupted by a scan tool dropout or a tool that lost power mid write
• Low system voltage during the procedure, which aborts the write before the module stores it
• A sensor bolted to the body loosely or shimmed by paint or undercoating, so the module rejects its reading
• A replacement sensor that is the wrong variant for the vehicle
• The sensor connector left unlatched after the swap

Crash data or hardware fault?

B1693 sits in the hardware group rather than the crash data group. Crash data gets written once during a deployment and stays locked in memory where no scan tool can reach it. This code describes a live condition the module reports at every power up when it finds the right side sensor unregistered, so finishing the initialization is what makes it go away.

Does our reset clear it?

Our mail in reset erases stored crash data and internal faults that are locked into module memory. B1693 is usually neither of those, since it points at a procedure that has to run on the vehicle with the sensor connected. Complete the initialization first. If the module also holds deployment data from a real crash, send it to us and we clear that side of it.

Which makes throw it

B1693 is a Lexus code, and Lexus is the only make our lookup carries it under. It applies to the side impact sensor mounted in the body structure on the right hand side of the vehicle.

What to do next

Confirm the sensor is the correct part for the vehicle and that it is bolted flat and plugged in, because the routine will not finish on a sensor the module cannot read cleanly. Then run the registration with a charger on the battery and a tool connection you trust. If the code survives a clean run, test the sensor and the module next, and we carry genuine OEM Lexus side impact sensors if the part turns out to be bad. Related codes: B1690, B1695, B1620.