B1020 on Nissan: How to Diagnose & Fix
Airbag/SRS Deployment Loop Fault (Manufacturer-Specific)
1 Nissan model · 1 documented issue · 1 critical · $250-$1,800 repair
B1020 on Nissan by model: symptoms, diagnosis and fix
Multiple 2007-2012 Altima owners report the air bag warning light flashing and the passenger air bag status behaving incorrectly due to faults in the occupant classification system (OCS) or related seat sensor components. This can disable the passenger frontal air bag when it should be enabled, or trigger a persistent SRS warning light. Nissan issued service information and warranty extensions on some related OCS concerns because the issue was common enough to generate many complaints and dealer repairs.
Common Symptoms
- air bag light flashing
- passenger air bag off light stays on with adult seated
- SRS warning light illuminated
- intermittent passenger air bag operation
- warning returns after battery disconnect
How to Fix
Diagnosis requires a capable scan tool that can read SRS and OCS data, not just generic OBD-II codes. Technicians typically inspect seat harness connections, zero-point calibration, seat cushion sensor mat operation, and the occupant detection control unit. Repairs may involve OCS recalibration, harness repair, or replacement of the passenger seat cushion/sensor assembly followed by SRS initialization.
Sources for this issue (1)
B1020 code reference
General diagnostic-code context. The code alone does not confirm a cause for your vehicle; use the applicable issue card and its sources.
Frequently asked questions
What does B1020 mean on a Nissan?
B1020 stands for "Airbag/SRS Deployment Loop Fault (Manufacturer-Specific)." B1020 is a manufacturer-specific body code; on GM-family vehicles it falls within the airbag (SIR/SRS) deployment-loop fault range, indicating the airbag module detected an electrical problem (such as a short or out-of-range resistance) in a deployment loop circuit. Because the exact loop and fault type vary by manufacturer and model, a make-specific scan tool and service manual are needed to confirm the precise circuit. As an SRS fault, the airbag warning light typically illuminates and proper airbag deployment may be affected, so it warrants prompt diagnosis. On Nissan it is documented across 1 model: Altima.
What are the most common causes of B1020?
The most common causes of B1020 are: Open, shorted, or high-resistance wiring in an airbag deployment loop, Corroded, wet, or loose connector in the SRS circuit, Faulty clockspring (for steering-wheel-mounted airbag circuits), Faulty airbag inflator/module, Faulty airbag (SRS/SDM) control module, Harness damage from prior repair or accessory work, Poor ground connection. The specific cause varies by vehicle.
How much does it cost to fix B1020 on a Nissan?
Published repair estimates on Nissan range from $250 to $1,800 depending on the model and root cause. If an issue mentions a recall or campaign, check your VIN with the manufacturer or NHTSA and confirm eligibility and coverage with a dealer.
Looking for B1020 on a different make?
View B1020 across all makes →Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.