B0020: Left Side Airbag Deployment Control
A generic body trouble code, same meaning on every brand.
Yes mechanically - but assume the side airbag on that side is disabled until repaired. Fix promptly; side impacts give no warning at all.
Symptoms
- Airbag warning light
- Code for the left side deployment loop
- Often appears after seat removal or upholstery work
- No driving symptoms
Likely causes, most common first
- Connector under the seat disturbed or corroded
- Seat-mounted airbag squib circuit fault
- Wiring chafed where the harness flexes with the seat
- Curtain airbag circuit fault on designs that route it here
Read B0020 yourself before paying for diagnosis
A basic Bluetooth OBD-II scanner ($20-40) plugs into the port under the dashboard and shows this code with live sensor data on your phone - useful both for confirming the fix and for talking to a shop from an informed position.
What is going on and how it gets diagnosed
B0020 concerns the deployment circuit of the left side airbag - on most designs the one built into the driver's seat bolster, on some the curtain above the window. The airbag computer watches loop resistance and retires the system when it drifts, exactly as with the frontal circuits.
What makes side airbag codes distinctive is geography: the wiring runs under the seat, through a connector that gets kicked by cargo, soaked by spilled drinks, and stretched every time the seat slides. If this code appeared after seat work, detailing, or moving something heavy under the seat, the connector is the prime suspect and sometimes the entire repair. The honest warning stands regardless of cause: while the light is on, plan as if that side airbag will not help you.
Repair options and cost
Typical US independent-shop ranges, parts and labor. Dealers run higher; regional labor rates vary.
Owner reports mentioning B0020
“Airbag light came on out of the blue. No accidents or anything done to cause light to come on just random. Was advised by dealership " FOUND CODE B0020 SIDE MODULE OPEN IN DRIVER SEAT AIR BAG, CODE IN PAST WHICH REQUIRES AIR BAG CONTROL UNIT REPLACEMENT-- NOTE AIR BAG SYSTEM IS DISABLED WHILE LIGHT IS FLASHING, NO AIR BACS WILL DEPLOY IN CASE OF ACCIDENT * REPLACE DRIVER'S SEAT AIR BAG ASSEMBLY AND AIR BAG CONTROL UNIT-- PARTS ARE SPECIAL ORDER. Was told it would be $3887.93 to fix. Why this is not a recall issue is beyond me especially given the amount of complaints as of recent and over the years regarding this same issue. Extremely disappointing!”2017 Infiniti QX80 · Jul 2026
“Airbag light unexpectantly came on without any collision action, or other unusual activity on 5/28/26. Delay getting car for inspection due to personal circumstances. On 6/29/26 car checked a nissan dealership. Inspected and checked codes. Coded as b0020-13 for air bag module defective. Recommended replacing driver side front seat back. This nissan altima 2017 not under recall, and call not under warranty. Safety of driver and passengers at risk.”2017 Nissan Altima · May 2026
“The vehicle show code B0020-13. This is a fault in the wiring system for the airbags. Caused by Jeep engineering being bad. This has nothing to do with how is driven or used and is a massive safety issue and shuts the entire airbag system down. It requires fix 10-001-20. This issue is so common they have issued a bulletin. The fix is $1100. The fact that this isn't covered by Chrysler is an abomination to safety and is absolutely ridiculous. Then being allowed to not fix air bag issue they know they have caused should be illegal. I'm embarrassed to even have to write this. This is going to kill someone.”2016 Jeep Cherokee · May 2026
Show 7 more owner reports
“Left Side Airbag Deployment control circuit - B0020 Right Side Airbag Deployment control circuit - B0028 Driver Seat Belt Sensor - Circuit open B0050 Occupant Classification System- missing message - BOOAO Driver Seat Track Position - BOOB5 Passenger Seat Belt Sensor - B0052”2016 Honda Odyssey · Apr 2026
“On December 26, 2025, the supplemental restraint system problem appeared on the dashboard. On January 6, 2026, vehicle was taken to Stockton Honda service department to performed a diagnostic test and multi-point inspection was completed. During this time the diagnostic results showed a code B0020-13, open or increased resistance in the left side airbag inflator. They recommend starting with the inflator replacement parts, SRS unit and program, and driver seat belt.”2020 Honda Accord · Dec 2025
“I am experiencing an issue with the airbag light on my 2017 Nissan Altima S model, which is showing code B0020. This airbag code indicates a problem with the passenger side airbag system, typically caused by damaged wiring, a malfunctioning seat sensor, or a loose connector beneath the driver's seat. The repair quote from my local Nissan dealership ranges from $1728 to $3500, depending on the faulty components and the labor required for installation. This is a recognized problem for Nissan, and their failure to address it raises significant concerns regarding safety. Currently, I am uncertain about how to proceed with the repair due to the high costs involved.”2016 Nissan Altima · Sep 2025
“Supplemental Airbag Warning Light solid red, does not go off. Occurred after oil change done at dealership 1/13/2025. Dealer found code B0020, recommended part 87650-3TD6G, seat back replacement, parts and labor for repairs $2,950.”2014 Nissan Altima · Aug 2025
“TRIM ELECTRICAL - Upon dealer service inspection, technician found the air bag light on. DTCS code B0020-13 left side airbag deployment control circuit open due to the wiring harness routed under the driver's seat becoming chafed as a result of the automatic seat adjustment resulting in a nondeployment or late deployment of airbag. Dealer recommended replacement of the wiring harness. THIS IS A DEFECTIVE DESIGN - this is a stock vehicle with 63k miles and normal use of moving the electronic driver's seat forward or back should not interfere with an airbag's performance.”2016 Land Rover Range Rover Sport · Sep 2024
“About two months ago, SRS/Supplmental Restrain light came on. It has been coming on/off. Took to the dealership to check; however at that time the light was off-they did not find anything wrong. ON 9/5/24, the light came on again, took to the dealership same day. They diagnosed as code B0020-13. Stated there is an "open or increased resistance in the left side airbag inflator. Installed SRS harness tester and found code to go away with SRS harness tool installed. As first step in diagnosis, recommend to replace left side airbag inflator and recheck. "”2018 Honda Accord · Jul 2024
“I'm getting an Air Bag warning light showing up on my dash. i took it to the Nissan dealer and its error code B0020-13 which comes up as a Left seat side air bag open error. Apparently the wiring going from the connector under the seat up to the side air bag is intermittently opening up depending what position the seat is in. Nissan said the entire top part of the seat needs to be replaced, very expensive, $2,500.00 to $3,000. This is a big safety problem since this is a common problem with this model from all the research I have done. This is obviously an engineering problem with how the cable is ran or quality of the cable and should be Nissans responsibility not the owner of the vehicle.”2018 Nissan Altima · May 2024
Cars that report B0020 most often
Based on mentions of this code in NHTSA owner complaints.
Frequently asked questions
Can I drive with B0020?
Yes mechanically - but assume the side airbag on that side is disabled until repaired. Fix promptly; side impacts give no warning at all.
How much does it cost to fix B0020?
Typical US repair costs range from $60 for the simplest fix (under-seat connector reseat or repair) to $900 in the worst case. The right number depends on which cause your car has - see the causes list.
Related codes
The codes closest to B0020. They often appear together, and telling them apart is usually what narrows the diagnosis.
Definition per SAE J2012 standard nomenclature. Symptoms, causes and costs are editorial guidance - always confirm with a diagnosis of your specific vehicle.