Code Definition

B1879 — Seatbelt Driver Pretensioner Circuit Short to Ground

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

About B1879

B1879 is a manufacturer-specific body diagnostic trouble code recorded for Ford vehicles. It belongs to the B-prefix family of codes, which covers body, interior, airbag, or comfort-electronics faults.

When B1879 is stored, the module has detected a short-circuit (voltage pulled to ground or to supply) in the monitored circuit.

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.

B1879 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

B1879 is set by the Restraints Control Module (RCM) when it detects that the driver side seat belt pretensioner squib circuit is shorted to ground anywhere between the RCM output pin and the pretensioner squib. The RCM independently monitors each squib lead for unintended low impedance paths to chassis ground, and a sustained short to ground will not only set this code but also prevent the pretensioner from firing reliably in a crash because the RCM cannot develop the required voltage across the squib element. The pretensioner is a pyrotechnic device built into the driver seat belt retractor o...

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