OBD-II trouble code
B0012: Passenger Frontal Stage 3 Deployment Control (Subfault)
The airbag/SRS control module detected an electrical fault in the passenger frontal airbag's third-stage deployment loop. The passenger airbag may not fire as designed, so this needs prompt professional attention.
Quick facts
- System
- Body
- Category
- Airbag / SRS Restraints
- Severity
- High severity
- Drivable
- Usually safe to drive short-term
- Repair cost range
- $100 – $900
- DIY difficulty
- Shop recommended
What does B0012 mean?
B0012 is a body (B) code stored by the airbag control module — the SDM (Sensing and Diagnostic Module) on GM vehicles or the Restraints Control Module on others. Its SAE-generic definition is 'Passenger Frontal Stage 3 Deployment Control,' referring to the deployment loop that fires the third stage of a multi-stage passenger frontal airbag. Many modern frontal airbags are staged: the module can fire them at different intensities depending on crash severity and occupant conditions, and each stage has its own electrical firing loop that the module continuously monitors.
The module sets B0012 when the resistance of that firing loop falls outside the tight window these pyrotechnic circuits require — an open circuit, a short to power or ground, or resistance that is too high or too low. Manufacturers append a symptom byte (for example :0D for open circuit, :01 for short to battery, :02 for short to ground) that pinpoints the exact nature of the fault, so always read the full code including its suffix. Because B-codes vary by manufacturer, confirm the exact definition against your make's service data; some GM tables associate B0012 with a driver-side loop instead.
This is a supplemental restraint fault, not a driveability fault: the vehicle drives normally, but the affected airbag stage may not deploy as intended in a crash, and airbag circuits carry a small risk of unintended deployment when mishandled. SRS diagnosis and repair should be performed by a qualified technician who can safely disable the system, and the fault should not be left unrepaired.
Common causes
- Corroded, backed-out, or loose connector at the passenger airbag or under the seat/dash
- Damaged wiring in the airbag firing loop (chafed, pinched, or previously repaired)
- Failed passenger frontal airbag inflator (squib) for the affected stage
- Fault in the yellow SRS connector or its shorting bar at the airbag
- Prior airbag deployment, dash work, or seat replacement that disturbed the loop
- Faulty airbag/SRS control module
Symptoms
- Airbag / SRS warning light on
- Stored B0012 fault (often with a symptom byte such as :0D) in the restraints module
- No effect on engine or driving performance
- Possible additional frontal or side deployment codes stored alongside it
Diagnostic steps
- 1.Use a scan tool that can access the airbag/SRS module and record B0012 and its full symptom byte along with any companion codes.
- 2.Confirm the exact definition and loop location for the specific make and model, since B0012 can map to different airbags across manufacturers.
- 3.With the system safely disabled per service procedure, inspect the passenger airbag connector and the yellow SRS harness for corrosion, backed-out terminals, or damage.
- 4.Check any connector under the dash or seat that was recently disturbed by service work.
- 5.Measure the deployment-loop resistance against specification to separate a wiring/connector fault from a failed inflator.
- 6.If the airbag or module was recently replaced, verify it is the correct part and was properly programmed to the vehicle.
- 7.Repair the wiring/connector fault or replace the indicated component, then clear codes and confirm the SRS light stays off.
Repair cost
$100 – $900
A connector or wiring repair is often modest, while a failed airbag inflator or module drives the cost up substantially. Diagnostic time on the SRS system typically runs $100-$200, and a passenger airbag or SDM/RCM replacement including programming can reach several hundred dollars or more. SRS work should be done by a qualified technician.
Estimate your repair
Run the numbers for your vehicle
Open the Repair Cost Estimator with airbag control module (sdm) replacement / reset preselected. Adjust labor rate and vehicle category to fit your situation.
DIY vs shop
Leave this one to a qualified shop. It typically involves emissions-critical components, refrigerant handling, or other work that requires manufacturer-grade tooling, training, or certification. DIY attempts often produce a more expensive problem than the original code.