B0043 – Left Front Side Impact Sensor Circuit Performance

DTC B0043 indicates that the Airbag Control Module (ACM) has detected a performance problem in the left front side impact sensor circuit. The sensor monitors side collision forces and sends information to the SRS module to help determine airbag deployment decisions.

This fault is related to the vehicle safety system and may affect the operation of side airbags during a collision.

Code Information

• DTC: B0043
• System: Supplemental Restraint System (SRS)
• Description: Left Front Side Impact Sensor Circuit Performance
• Severity: High (Safety Related)

Symptoms

• Airbag warning light stays ON.
• SRS warning message appears.
• Side airbags may be disabled.
• Fault code stored in the Airbag Control Module.
• No engine performance problems are usually present.

Possible Causes

• Defective left front impact sensor.
• Sensor signal out of expected range.
• Damaged wiring harness.
• Loose or corroded connector.
• Previous accident damage.
• Airbag Control Module internal fault.

Typical Wiring Diagram

🔴 B+ Power
┃
┏━━━━━━━━━━━━━━┓
┃ Airbag ECU ┃
┗━━━━━━┳━━━━━━━┛
┃ 🟡 Signal
┏━━━━━━┻━━━━━━━┓
┃ Left Front ┃
┃ Impact Sensor┃
┗━━━━━━┳━━━━━━━┛
┃ ⚫ Ground
┃
Vehicle Chassis

Diagnostic Procedure

1. Scan the vehicle and confirm B0043 is stored.
2. Check the SRS system for additional related codes.
3. Inspect the left front impact sensor and connector.
4. Check for corrosion, damaged terminals, or water intrusion.
5. Test wiring continuity between the sensor and Airbag ECU.
6. Verify sensor operation according to manufacturer specifications.
7. Replace the sensor if it fails testing.
8. Clear codes and confirm the repair.

Important Note

Sensor location, connector pinout, wire colors, and electrical values vary between vehicle makes and models. Always use factory service information before testing SRS circuits.

Can You Drive With B0043?

The vehicle may drive normally, but the SRS system may not provide full protection in a collision. Repairing this fault is recommended as soon as possible.

Estimated Repair Cost

• Connector repair: $20–80
• Wiring repair: $40–150
• Impact sensor replacement: $80–300
• SRS module replacement if required: $300–900

Related DTCs

• B0040
• B0041
• B0042
• B0044

Frequently Asked Questions

What causes B0043?

The most common causes are sensor failure, wiring problems, connector issues, or collision damage.

Can I clear B0043 with a scanner?

You can clear the code, but it will return if the electrical problem has not been repaired.

Is B0043 dangerous?

Because it affects the SRS system, it should be considered a safety-related fault and repaired properly.

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OBDSpark Technician Tip: Never apply external power or use a test light on airbag circuits. Follow manufacturer safety procedures before servicing SRS components.