Damaged or disconnected wiring harness at the third row left seat or pillar, often from seat movement or cargo loading.; Corroded or loose electrical connector at the airbag module or the seat-mounted inflator.; Failed clock spring or spiral cable if the circuit is routed through the steering column (less common for third row).; Internal fault in the airbag inflator's squib, causing out-of-range resistance.; Water intrusion or corrosion in the connector or wiring due to a leak in the third row area.; Faulty SRS control module, though this is rare and should be diagnosed last.; Aftermarket accessories or previous repairs that tapped into the SRS wiring improperly.

DTC codes / B00xx · Airbags, seats, doors, lights and comfort systems / B0043

B0043Third Row Left Frontal Stage 3 Deployment Control

Q: What does code B0043 mean?

Third Row Left Frontal Stage 3 Deployment Control. B0043 indicates that the supplemental restraint system (SRS) control module has detected a fault in the deployment circuit for the third row left frontal stage 3 airbag, which is a pyrotechnic device designed to fire in certain crash scenarios. The computer monitors the circuit's resistance and continuity, and when the readings fall outside the expected range, it stores this code and typically disables the affected airbag to prevent accidental deployment.

B0043 indicates that the supplemental restraint system (SRS) control module has detected a fault in the deployment circuit for the third row left frontal stage 3 airbag, which is a pyrotechnic device designed to fire in certain crash scenarios. The computer monitors the circuit's resistance and continuity, and when the readings fall outside the expected range, it stores this code and typically disables the affected airbag to prevent accidental deployment.

SystemBody

Code typeGeneric (all makes)

SeverityMedium

Fix difficultyProfessional

AreaAirbags, seats, doors, lights and comfort systems

Symptoms you may notice

The airbag warning light on the instrument cluster stays illuminated after the bulb check.
A message such as 'Service Airbag' or 'SRS Fault' may appear on the driver information center.
Often no symptoms besides the warning light, with the vehicle driving normally.
The affected third row left frontal airbag will not deploy in a crash, reducing occupant protection.
In some vehicles, other airbags in the same circuit group may also be disabled as a precaution.
Intermittent warning light operation if the fault is a loose connection or chafed wire.

Common causes, most likely first

Damaged or disconnected wiring harness at the third row left seat or pillar, often from seat movement or cargo loading.
Corroded or loose electrical connector at the airbag module or the seat-mounted inflator.
Failed clock spring or spiral cable if the circuit is routed through the steering column (less common for third row).
Internal fault in the airbag inflator's squib, causing out-of-range resistance.
Water intrusion or corrosion in the connector or wiring due to a leak in the third row area.
Faulty SRS control module, though this is rare and should be diagnosed last.
Aftermarket accessories or previous repairs that tapped into the SRS wiring improperly.

How to diagnose and fix it

Connect a scan tool capable of reading SRS codes and record all stored and pending codes, then clear them to see if B0043 returns immediately.
Visually inspect the third row left seat area for obvious wiring damage, pinched harnesses, or disconnected connectors, and check for signs of water intrusion.
Disconnect the battery and wait the manufacturer-specified time, then carefully inspect and reseat the connector at the third row left airbag inflator.
Measure the resistance of the airbag squib circuit with a digital multimeter (following service information) to check for open or short circuits; compare to specification.
If resistance is out of range, perform a wiggle test on the harness while monitoring resistance to locate intermittent faults.
Repair or replace damaged wiring or connectors as needed, using proper crimping and heat-shrink techniques, then clear codes and verify the warning light goes out.
If the circuit tests good, substitute a known-good airbag inflator (following safety procedures) to see if the code changes; if not, diagnose the SRS control module.

Hidden causes of third row airbag faults

A common oversight is failing to check the wiring under the third row seat for damage caused by cargo or seat folding mechanisms, which can chafe the harness and set this code.
The code does not always mean the airbag itself is bad; often it is a simple connector issue or a poor ground that can be fixed without replacing expensive components.
Technicians sometimes replace the airbag only to find the code returns because the root cause was a corroded pin in the connector, so always inspect and test the circuit thoroughly.
Water leaks from a rear window or liftgate seal can corrode the third row airbag connector, leading to this code, so check for dampness or rust in the area.
After a collision repair, improperly routed or pinched wiring in the third row can trigger B0043, so review repair history and inspect harness routing.

Can I keep driving with B0043?

The vehicle is generally safe to drive because the airbag system is designed to disable only the affected circuit, but you should avoid any situation that could trigger a crash until the fault is repaired. Have the system diagnosed promptly, as the third row left frontal airbag will not deploy in a collision, reducing protection for that occupant.

Tools that help

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Guidance is general and written for all OBD-II vehicles. Exact tests and values vary by model, so confirm the fault before replacing parts.