B1019: How to Diagnose & Fix — SDM System Configuration Error
2 vehicles · 2 makes · $150-$5,000 repair
How to diagnose and fix B1019: 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.
Cadillac XTS · 2013–2019
XTS HID/Xenon headlamps suffer ballast (HID control unit) failures and headlight-housing condensation that cause intermittent or total loss of a low beam. Owners report flickering, a headlamp that cuts out then comes back, or a dead side after a new bulb. Moisture entering the housing is a frequent root cause — water reaching the ballast causes rapid failure — and corrosion in the headlight wiring/ground (often shared with the upper LED DRL) can take out both the ballast and DRL together.
Common Symptoms
- One low-beam HID out or flickering
- Headlight cuts out then comes back
- Condensation/water inside headlamp
- Upper DRL out on the same side
- New bulb still doesn't fix it
- Pinkish/dim HID color before failure
How to Fix
Diagnose by swapping the D3S bulb side-to-side; if the fault follows the position, the ballast/igniter is bad, not the bulb. Replace the failed HID ballast/control module and reseal the housing; dry out and re-gasket any housing showing condensation. Inspect the ballast connector and chassis ground for corrosion and repair before installing new parts, or the new ballast will fail again. Use OEM-grade D3S bulbs and a matching ballast to avoid color/flicker issues.
Sources for this issue (1)
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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B1019 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 B1019 mean?
B1019 stands for "SDM System Configuration Error." General Motors definition. At every ignition cycle the Sensing and Diagnostic Module (SDM, the airbag control module) compares the restraint configuration stored in its memory against the restraint hardware it actually sees on the SRS circuits — deployment loops, impact sensors, pretensioners and seat/occupant hardware. B1019 sets when the detected configuration does not match the programmed configuration, and the SDM disables the entire restraint system so that nothing can deploy incorrectly. Note: this GM definition does not apply to Nissan, where B1019 is used for the Occupant Classification System (OCS) control unit / sensor mat and its link to the airbag diagnosis sensor unit; scope the code to the correct manufacturer before acting on it.
What are the most common causes of B1019?
The most common causes of B1019 are: Airbag control module (SDM) replaced with a unit not programmed/configured to the vehicle's build, A restraint component (seat-mounted airbag, pretensioner, impact sensor, occupant sensing hardware) unplugged, missing or substituted with the wrong part, Damaged or corroded SRS connector under a seat, or a yellow SRS connector not fully latched after seat/interior work, Wrong-VIN or incorrect calibration loaded into the SDM after a repair, Internal SDM fault. The specific cause varies by vehicle.
How much does it cost to fix B1019?
Repair costs for B1019 range from $150 to $5,000, depending on the vehicle and root cause.
Which vehicles are affected by B1019?
Au7o has documented B1019 across 2 vehicle models from 2 manufacturers: Cadillac, Nissan.
Content compiled with AI assistance using NHTSA complaints, TSBs, and owner reports. May contain errors. Always verify with your vehicle's service manual.