B1018: How to Diagnose & Fix — Passenger Deployment Loop Short to Ground (Manufacturer-Specific)
2 vehicles · 1 makes · $500-$5,000 repair
How to diagnose and fix B1018: most-reported vehicles
Ranked by owner reports. Each card gives the symptoms, how to confirm the cause, the fix, parts and sources for that vehicle.
Nissan Altima · 2007–2012
Owners report the air bag warning light flashing or the 'passenger air bag off' indicator staying lit with an adult in the seat; dealers and mechanics traced it to the occupant sensor in the passenger seat cushion, and some owners were told the whole cushion must be replaced. Owners say they were told the passenger air bag may not deploy while the fault is present. 2007-2012 Nissan Altima (L32) sedan and coupe, based on owner reports. Separately, 2007-2008 Altima and Altima Coupe built March 12, 2007 to May 27, 2008 were covered by recall 08V521 (occupant classification control unit in the passenger seat cushion); eligibility is by VIN.
How to Fix
Have a dealer or qualified technician read the air bag system codes and repair the occupant classification system; this is a safety system, so do not attempt a DIY reset. For a 2007-2008 car, ask a Nissan dealer to check the VIN for recall 08V521: the dealer tests the occupant classification signal with a special tool and, if necessary, replaces the passenger seat cushion containing the sensor hardware. Summarized from the owner reports linked here; not a manufacturer finding. Your vehicle's equipment and history may differ; a technician must confirm the cause. The separate 08V521 recall does not extend to a 2010 vehicle just because it has a similar warning. Do not use a reset or an illustration to decide that the passenger airbag is working.
Call to confirm they can assess your vehicle and perform the stated work. Search results do not confirm qualification, eligibility or coverage.
Sources for this issue (4)
- NHTSA owner complaints, 2010 Nissan Altima (ODI 11156041, 11031591, 11280909, 11506209)nhtsa
- NHTSA owner complaints, 2009 Nissan Altima (ODI 11512062, 11268204)nhtsa
- CarComplaints: 2010 Nissan Altima air bag light onforum
- Nissan Part 573 defect report 08V-521, occupant classification control unit (2007-2008 Altima)recall
Nissan Leaf · 2011–2012
The passenger seat's Occupant Classification System (OCS) sensor mat can fail, causing the 'Passenger Airbag OFF' light to stay illuminated even with an adult in the seat, deactivating the passenger airbag. NHTSA opened (and later closed) an investigation into 2011-2012 Leafs for this defect, and owners set a B1018 seat-sensor DTC. Nissan recalled 2013-2016 Leafs for a related airbag/OCS issue but excluded 2011-2012 because the system differs, leaving those owners to pay out of pocket. The costly part: the OCS mat is integrated into the seat, so the fix often requires replacing the entire passenger seat (owners report $3,000-$5,000).
Common Symptoms
- 'Passenger Airbag OFF' light stays on with an adult in the seat
- Airbag warning light illuminated
- B1018 seat/occupant sensor DTC stored
- Intermittent switching of the passenger airbag status
How to Fix
Scan for B1018/OCS codes. Repair the OCS sensor mat/harness if possible; in many cases Nissan only offers passenger-seat (or seat cushion with integrated sensor) replacement plus recalibration. Some independent specialists can repair or replace just the sensor mat at lower cost. Do not ignore — the passenger airbag will not deploy while the light shows OFF.
What you need to fix it
Only diagnosis- and fitment-reviewed repair parts are linked here.
- Genuine Nissan 2011-2012 LEAF front passenger seat cushion with OCS 87300-3NA8A
Confirm VIN, seat trim/options and calibration capability.
As an Amazon Associate, we earn from qualifying purchases; other part links may also earn au7o a commission. Confirm fitment by VIN before buying.
Sources for this issue (3)
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B1018 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 B1018 mean?
B1018 stands for "Passenger Deployment Loop Short to Ground (Manufacturer-Specific)." B1018 is a manufacturer-specific SRS/airbag code that, on GM-family vehicles, indicates the passenger airbag deployment loop circuit is shorted to ground. The airbag module continuously monitors the resistance of each deployment loop, and a short to ground in the passenger circuit is an electrical fault that can prevent proper deployment. The airbag warning light will be on and the passenger airbag may not fire correctly in a crash, so it should be diagnosed promptly.
What are the most common causes of B1018?
The most common causes of B1018 are: Chafed or pinched wiring shorting the passenger deployment loop to ground, Corroded or wet connector in the passenger airbag circuit (often the clockspring or under-dash connector), Faulty passenger airbag inflator/module, Damaged harness from prior repair or accessory installation, Loose or backed-out connector pin, Faulty airbag (SRS/SDM) control module, Water intrusion at a floor or seat connector. The specific cause varies by vehicle.
How much does it cost to fix B1018?
Repair costs for B1018 range from $500 to $5,000, depending on the vehicle and root cause.
Which vehicles are affected by B1018?
Au7o has documented B1018 across 2 vehicle models from 1 manufacturers: Nissan.
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Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.