B0042: Side Deployment Loop Open (Generic)
A generic open-circuit fault has been reported in a side airbag deployment loop. Refer to vehicle service data to determine the affected side and stage.
What B0042 means
B0042 is a generic OBD-II body code in the airbags & restraints group. In plain English: the computer found an electrical fault in that circuit: an open, short or bad connection, or a failed component.
- Check engine light
- Usually off
- Emissions-related
- No
- Limp mode possible
- Not typical
- Drive cycle to clear
- Not required
Get it fixed
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Symptoms
- Warning light or symbol related to the affected system
- Comfort or safety function impaired
Common causes
- 01Disconnected seat connectorMost likely
- 02Broken wire in seat harnessPossible
Can I drive with B0042?
The car drives, but it is a safety risk.
With an airbag or restraint fault stored, one or more airbags or pretensioners may not deploy in a crash. Get it diagnosed soon and do not ignore a lit airbag light.
Why we rate it urgent
- An airbag or seat-belt pretensioner may not work in a crash
- Does not normally turn on the check engine light
Severity is our rule-based rating from the code’s flags in OBDex and the system it affects, not an inspection of your car. If the check engine light is flashing, or you notice overheating, low oil pressure, or brake or steering problems, stop driving and get help.
How to diagnose B0042
- 1
Confirm the code and save freeze-frame data
Read the codes with an OBD-II scan tool and note every code, not just B0042. Save the freeze-frame data (speed, load, temperature when the fault set) before clearing anything; it tells you when the fault happens.
- 2
Fix other faults first
If other codes are stored, start with power-supply, sensor-circuit and communication codes. They can cause this code as a side effect.
- 3
Test the circuit
Inspect the wiring and connector at the side airbag and srs seat wiring for damage, corrosion or chafing. With a multimeter, check supply voltage, ground and signal against the specifications in the service manual for your vehicle.
- 4
Test the likely causes in order
Start with the most likely cause and work down: Disconnected seat connector; broken wire in seat harness. Test before replacing parts.
- 5
Check for recalls and service bulletins
Look up recalls for your exact vehicle with its VIN, and ask a dealer about technical service bulletins (TSBs). Manufacturers sometimes issue software updates or extended warranties for known faults.
- 6
Clear the code and verify the repair
After the repair, clear the code and drive the car under the conditions in the freeze-frame data to confirm it does not return.
B0042 repair cost estimate
Estimate, not a quote. Labor times are typical ranges for this code from OBDex, and $125/hr is an assumed rate. Shop rates and labor times vary by vehicle and region. Diagnosis time may be billed separately.
- DIY difficulty
- Hard
- Good DIY job?
- Usually a shop job
Involved testing or major parts. Most owners use a shop.
Parts and systems involved
- Side airbag
- SRS seat wiring
B0042 FAQ
What does B0042 mean?
B0042 means “Side Deployment Loop Open (Generic)”. A generic open-circuit fault has been reported in a side airbag deployment loop. Refer to vehicle service data to determine the affected side and stage.
Is B0042 serious? Can I keep driving?
We rate B0042 as urgent severity. The car drives, but it is a safety risk. With an airbag or restraint fault stored, one or more airbags or pretensioners may not deploy in a crash. Get it diagnosed soon and do not ignore a lit airbag light.
What causes B0042?
The most common causes, from most to least likely: Disconnected seat connector; Broken wire in seat harness. Test before replacing parts, because several causes can set the same code.
How much does it cost to fix B0042?
Typical labor is about $90–$315 at an assumed $125/hour shop rate, plus parts. That is an estimate, not a quote: labor times and rates vary by vehicle and region, and diagnosis may be billed separately.
Can I fix B0042 myself?
DIY difficulty is hard. Most owners leave this to a shop because it needs involved testing or specialist tools. Always confirm the cause before buying parts.
Will B0042 clear itself?
If the fault was intermittent, the warning may go off once the computer stops seeing it, but the code stays in memory. Fix the cause; clearing the code alone doesn’t repair anything.