Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means there's a problem with the airbag system in the back left seat of the car. The airbag might not work properly if there's an accident.
The B0040 code indicates an issue with the airbag system's ability to deploy the airbag located on the left side of the third row of seats.
The B0040 code is triggered when the airbag control module detects a fault in the deployment circuit for the third row left side airbag. This can be due to electrical issues, such as open or short circuits, or a failed airbag module.
• Airbag warning light on
• Airbag may not deploy in a crash
• Error code stored in the vehicle's computer
• Faulty airbag module
• Wiring issues
• Faulty airbag control unit
Airbag: A safety device in vehicles that inflates rapidly during a collision.
Deployment: The action of an airbag inflating during an accident.
• Perform a visual inspection of the airbag system wiring.
• Use a diagnostic scanner to read and clear the code.
• Test the airbag module and control unit for faults.
• Replace faulty airbag module.
• Repair or replace damaged wiring.
• Replace the airbag control unit if necessary.
• Diagnostic scanner
• Multimeter
• Wiring repair kit
$200 - $600
Moderate
• Chevrolet Suburban
• GMC Yukon XL
• Cadillac Escalade ESV
• Regularly inspect airbag system wiring.
• Ensure no water or moisture enters the vehicle's interior.
• Have airbags checked during routine maintenance.
Safety System Issue
• Do not ignore the airbag warning light.
• Have the vehicle inspected by a professional if the airbag light is on.
• Avoid tampering with the airbag system yourself.
Airbag systems are often covered under extended warranties due to safety regulations.
Airbag deployment issues have been a concern since the introduction of advanced airbag systems in modern vehicles.
High – Airbags are a critical safety feature, and any issues should be addressed immediately.
Driving with a malfunctioning airbag system can be dangerous and may not comply with safety regulations.
• Vehicle must be stationary.
• Battery should be fully charged.
The third row left side airbag is located in the rear left section of the vehicle, typically in the side panel or seat.
Q: Can I drive with the B0040 code?
A: It's not recommended as the airbag may not deploy in an accident, which is a safety risk.
Q: How do I reset the airbag light?
A: A professional diagnostic tool is needed to reset the airbag light after repairs are completed.
Pro · Four-system diagnostics
A handheld scanner aimed at engine, transmission, ABS, and airbag diagnostic work.
Body and airbag faults often need a scanner that can access more than generic powertrain codes.
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Universal · Digital multimeter
A solid entry-level multimeter for voltage, continuity, resistance, and basic electrical troubleshooting.
Helpful for checking power, ground, and continuity in body-system circuits.
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Universal · Fuse kit
Useful for electrical diagnosis when blown fuses or circuit faults are part of the troubleshooting process.
Useful when body electrical faults trace back to blown fuses or shared circuits.
View on AmazonThese are optional diagnostic tools, not guaranteed fixes. As an Amazon Associate I earn from qualifying purchases.