OBD-II B-codes are Body trouble codes tied to interior and body electronics — especially airbags / SRS, seat belts, HVAC actuators, door locks, keyless entry, and lighting, most of which run through the Body Control Module (BCM). Unlike powertrain P-codes, most B-codes are manufacturer-specific, so the same number can mean different things across makes. Use this hub to find the right subsystem and confirm the definition for your exact year, make, and model.
Many entry-level OBD-II readers only show engine/emissions P-codes. If you have an airbag light, a body warning, or an interior-electronics fault, you typically need a scanner that can access the BCM, SRS, and HVAC modules — not just the engine ECU.
Airbag / SRS safety: If an airbag light is on, the system may be disabled. Do not probe airbag wiring, connectors, or inflators without the proper service procedures — capacitors can hold a charge and an accidental deployment can cause serious injury. When in doubt, leave SRS work to a qualified technician.
Browse B-Codes by Subsystem
Each subsystem groups the body codes that share the same root cause and diagnostic approach.
These code families map to the most-searched SRS, seatbelt, and occupant issues. Definitions can vary by make and model, so always confirm against your specific vehicle.
Best practice: For B-codes, the scan tool matters more than the code. Most body faults live in the BCM, SRS, or HVAC modules, which entry-level readers can’t reach. If your scanner won’t display B-codes, you likely need an SRS-capable tool.
Need a scanner that reads Body & SRS codes?
Body and airbag faults require a tool that accesses the BCM and SRS modules — not just the engine ECU.
B-codes are Body trouble codes tied to interior and body electronics — airbags (SRS), seat belts, HVAC actuators, door locks, keyless entry, lighting, and other systems usually controlled by the Body Control Module (BCM).
Many entry-level readers only access the engine computer and show P-codes. B-codes live in modules like the BCM, SRS, and HVAC controllers, so you generally need a scan tool that can read those modules.
Often not. Generic powertrain codes (P0xxx) are standardized by SAE, but many B-codes and their definitions vary by manufacturer and module. Confirm the meaning using your exact year, make, model, and scan tool details.
Use caution. If the airbag light is on, the system may be disabled. Avoid probing airbag wiring, connectors, or inflators without the proper procedures. Start only with safe checks — like battery condition and visible connector inspection — and leave deeper SRS work to a qualified technician.
Clearing a code doesn’t fix the underlying fault, and many SRS warnings will return on the next key cycle if the problem is still present. With safety systems especially, the goal is to diagnose and repair the cause, not silence the light.
