B1630 reports a fault in one of the rear mounted satellite sensors that feed the curtain shield airbags. Lexus and Toyota print it as B1630/23. The same part carries different names depending on which repair manual you are holding.
The description of the part stays consistent even when the name does not. The sensor contains a safing sensor, a diagnostic circuit, and a lateral deceleration sensor. When the airbag ECU assembly receives signals from that lateral deceleration sensor, it decides whether the restraint system should be activated. The sensor sits back in the body and reaches the module through the floor wire.
The detection condition in the 2004 Prius manual explains why one number covers four separate electrical failures. The code is recorded when the airbag sensor assembly receives a line short signal, an open signal, a short to ground signal, or a B plus short signal in that sensor circuit for two seconds. The trouble areas listed are the floor wire, the rear airbag sensor, and the airbag ECU assembly.
Which side B1630 covers depends on the vehicle. The 2007 FJ Cruiser manual titles B1630/23 as Driver Side Rear Airbag Sensor Malfunction and names the rear airbag sensor LH in its trouble area. Toyota 4Runner service data lists B1630/23 as the rear airbag sensor RH with B1635/24 as the LH. Read the manual for the vehicle in front of you before ordering, because the twin code covers the opposite side either way.
Hardware, with the wiring as the other half of the diagnosis. Nothing about B1630 is a stored crash record. The module is reporting what a sensor circuit reads right now.
The overlap with collision work is that these sensors live where side impacts land. A vehicle that took a hit on one side often comes back with B1630 or B1635 after the body work, because the sensor took the impact and went back in during the rebuild. When the curtain airbags on that side deployed, the module is also holding a locked deployment record, which is a second job on the same repair order.
No. Clearing memory does nothing for a sensor circuit reading out of range, and the code returns on the next key cycle. Repair or replace the sensor and its wiring first.
Once the hardware is right, the crash side of the job is ours. If the curtain airbags deployed and the module locked, our airbag module reset clears the stored crash data from your original module so it goes back into the same vehicle. Genuine OEM impact sensors are searchable by vehicle in the parts store.
B1630/23 is a Lexus and Toyota number and it runs across a long span of model years, from the 2004 Prius through the trucks and SUVs of the following decade. Lexus documentation for this range uses the curtain shield wording, and several Toyota manuals covering the same years call the identical part a rear airbag sensor. Subaru also carries B1630 in its own airbag chart for a curtain airbag sensor RH failure, so confirm the make before acting on anything here.
Work the trouble area list in the order the manual gives it. Check the floor wire and the sensor connector before condemning the sensor, since that wiring reaches the back of the vehicle and passes every place cargo, seat bolts, and carpet work can reach it.
If B1635 is stored at the same time, both rear sensors are affected and the shared harness or the module moves ahead of the sensors on your list. On vehicles with door mounted side sensors, B1620 covers a different sensor in the same system and is easy to confuse with this one.
Related codes: B1635, B1620, B1650
Keep reading:
Code scope: Lexus. The same number can mean something different on another manufacturer, so match the code to your make before you act on it.
A reset clears stored crash data. A replacement part fixes a hardware fault. We have read these codes since the nineties and will tell you which one you are looking at.
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