Code Definition

B1999 — Passenger Side, Side mount Airbag Low resistance on Squib

System: Body  |  Type: Manufacturer-Specific  |  Make: Generic

About B1999

B1999 is a manufacturer-specific body diagnostic trouble code. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1999 is stored, the module has detected a signal or supply voltage lower than the expected operating range.

Scanning & clearing: Body (B) codes are often stored in the body control module, airbag module, or climate module. A basic OBD-II tool usually will not read body codes — an enhanced or OEM-level scan tool is typically required.

B1999 is a manufacturer-specific code. The same code string on a different make may have a different meaning. Always confirm the code's definition against the vehicle's service information for the specific make and model under test.

Code Information

The Supplemental Restraint System (SRS) control module monitors the deployment squib resistance of the passenger side mount (side impact) airbag continuously. The squib is the small heating element inside the airbag inflator that ignites the propellant when commanded. Code B1999 sets when the SRS module measures squib resistance below the expected window (the lower threshold is typically around 1.5 ohms, though the exact value varies by manufacturer). A low resistance reading indicates a partial internal short within the squib or shorted wiring between the conductors of the deployment pair. Wh...

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