OBD-II trouble code
B0029: Right Curtain Deployment Control 1 (Subfault)
The airbag/SRS control module detected an electrical fault in the right-side curtain airbag deployment loop. The roof-rail curtain airbag may not deploy 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 B0029 mean?
B0029 is a body (B) code stored by the airbag control module. Its SAE-generic definition is 'Right Curtain Deployment Control 1,' referring to the firing loop that deploys the right-side curtain (roof-rail) airbag — the long airbag that drops along the passenger-side windows to protect occupants' heads in a side impact or rollover. It is the right-side mirror of B0021 (Left Curtain Deployment Control 1). The '1' distinguishes it from a second right-curtain loop (B002A) on vehicles that use more than one deployment circuit. The module monitors this loop continuously and stores B0029 when its electrical condition is out of specification. As with all B-codes, confirm the exact application against your make's service data.
The module sets the code when the deployment loop's resistance 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. A symptom byte appended to the code identifies the exact fault type. Because a curtain airbag runs the length of the roof rail, its firing loop and connector are routed up the A-pillar and along the headliner on the passenger side, where connectors can be disturbed by pillar-trim removal, headliner work, or collision repair.
This is a supplemental restraint fault, not a driveability fault: the vehicle drives normally, but the right curtain airbag 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 curtain airbag (right A-pillar or roof rail)
- Damaged wiring in the curtain firing loop after trim, headliner, or collision work
- Failed curtain airbag inflator (squib)
- Fault in the SRS connector or its shorting bar at the airbag
- Prior side-impact damage or repair that disturbed the loop
- Faulty airbag/SRS control module
Symptoms
- Airbag / SRS warning light on
- Stored B0029 fault (often with a symptom byte) in the restraints module
- No effect on engine or driving performance
- Possible additional side or curtain deployment codes stored alongside it
Diagnostic steps
- 1.Use a scan tool that can access the airbag/SRS module and record B0029 with its full symptom byte and any companion codes.
- 2.Confirm the right curtain loop and airbag location for the specific make and model.
- 3.With the system safely disabled per service procedure, inspect the curtain airbag connector at the right A-pillar and along the roof rail for corrosion, backed-out terminals, or damage.
- 4.Check any pillar trim or headliner that was recently removed, since curtain-loop connectors are commonly disturbed during that 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 the correct part and proper programming.
- 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 repair at the A-pillar can be modest, while a failed curtain inflator or control module is much costlier. SRS diagnostic time typically runs $100-$200, and a curtain airbag or SDM/RCM replacement with 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.