B0073 on GM vehicles reports a fault in the right front seat belt sensor circuit, meaning the switch that tells the module whether the passenger belt is buckled. It is an input circuit, not a firing circuit, so no airbag is sitting on the other end of it. The module still cares, because belt status changes how it decides to deploy.
GM puts the inflatable restraint seat belt switch inside the belt retractor. The sensing and diagnostic module supplies a low reference circuit and a seat belt switch signal circuit, then reads the state of that switch to know whether the passenger is belted. B0073 covers the right front position and B0072 covers the left front.
The symptom bytes on this one are slightly different from the deployment loop codes. GM lists 01 for short to battery, 02 for short to ground, 04 for open circuit, 06 for short to ground or open, and 08 for an invalid signal. An invalid signal usually means the module is seeing a state that does not make sense, such as a switch that never changes.
Because belt use feeds into deployment strategy on a modern SIR system, a module that cannot trust the passenger belt input flags the fault and turns on the airbag light. The belt reminder chime and indicator often act strange at the same time, which is a useful clue that the switch and not the airbag side is at fault.
Circuit and hardware. B0073 is the module reporting the electrical condition of a switch input, so the repair is at the belt, the connector, or the wire between them. It carries no crash information by itself. On a vehicle that has been in a collision you may see it beside real crash data, but that is coincidence of the same accident damaging the harness, not a link between the two.
No. This one is not stored crash data, so restoring the module does not help and the code sets again on the next key on. The repair is at the passenger belt. Our seat belt repair service covers retractor and buckle work for mail in belts, and genuine OEM seat belt assemblies for GM vehicles are in the parts store. If the module is also holding a deployment record from an accident, that part of the job is separate.
The right front seat belt sensor wording comes from GM service information for Chevrolet, GMC, Buick, and Cadillac vehicles, and it is documented on the full size trucks of the late 2000s. Some older GM SIR references list this number for something else entirely, so check the code against the service data for your specific year and platform. Other manufacturers use B0073 for unrelated circuits.
Buckle and unbuckle the passenger belt while watching the seat belt switch status on a scan tool. A switch that never changes state, or one that flickers when you push on the retractor, tells you what you need to know without pulling any trim. Then check the connector under the seat, since seat travel is the usual reason a good switch reads bad.
Related codes worth checking: B0072 for the driver side switch, and B0052, which is used by some manufacturers for a seat belt sensor fault and by others for a deployment record.
Related codes: B0058, B0070, B0052
Keep reading:
Code scope: Chevrolet, GMC, Cadillac, Buick. 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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