What it means
Fault on the second-row right frontal airbag, stage 1 deployment (low severity). Found on vehicles with rear-passenger frontal airbags integrated in the front seatbacks.
At a glance
- Usually lights the airbag (SRS) or body-system warning light
How it works
The restraint control module monitors stage 1 of the second-row right frontal airbag circuit, often housed in a front seatback for rear-passenger protection. B0039 indicates an electrical fault in that stage 1 deployment path; the subfault information specifies the detected condition.
Common causes
Most likely first.
- Open or high resistance in the stage 1 inflator circuit
- Damaged wiring or connector at the airbag or restraint control module
- Loose or corroded connector
- Fault in the restraint control module
Symptoms
- Warning light or symbol related to the affected system
- Comfort or safety function impaired
How to diagnose it
- Read the SRS subfault and event data to confirm stage 1 of the second-row right frontal airbag is affected.
- Inspect the right seatback airbag area and wiring for damage, pinching, prior upholstery work, or a connector disturbed by seat movement.
- Disable the SRS following the manufacturer's procedure, then check accessible stage 1 connectors for looseness, corrosion, or harness damage.
- Use approved SRS test equipment to test stage 1 for an open, short, or resistance outside the manufacturer's specification.
- If the harness passes, check the airbag module and restraint control module using the prescribed procedure, then clear and rescan.
Common fixes
- Secure a loose stage 1 connector or repair damaged right seatback wiring using the approved SRS method.
- Repair a confirmed open or short in the second-row right stage 1 circuit.
- Replace the right frontal airbag module if its stage 1 circuit fails the specified test.
- Replace or program the restraint control module only after the stage 1 circuit and module are verified.
Can I keep driving?
Stage 1 of the second-row right frontal airbag may not work as intended, reducing protection for rear occupants in a crash. Arrange prompt SRS repair and avoid disturbing the seatback wiring.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.