B0042 – Right Front Side Impact Sensor Circuit Malfunction

DTC B0042 indicates that the Airbag Control Module (ACM) has detected an electrical fault in the right front side impact sensor circuit. This sensor measures side-impact forces and communicates with the Supplemental Restraint System (SRS) to determine whether the right-side airbags should deploy during a collision.

Code Information

• DTC: B0042
• System: Supplemental Restraint System (SRS)
• Description: Right Front Side Impact Sensor Circuit Malfunction
• Severity: High (Safety Related)

Symptoms

• Airbag warning light illuminated.
• SRS warning message displayed.
• Right-side airbags may be disabled.
• B0042 stored in the Airbag Control Module.
• No noticeable engine performance issues.

Possible Causes

• Failed right front side impact sensor.
• Open or shorted sensor wiring.
• Loose or corroded electrical connector.
• Damaged wiring harness after a collision.
• Internal Airbag Control Module fault (rare).

Typical Wiring Diagram

B+ Power
┃
┏━━━━━━━━━━━━━━┓
┃ Airbag ECU ┃
┗━━━━━━┳━━━━━━━┛
┃ Signal
┏━━━━━━┻━━━━━━━┓
┃ Right Front ┃
┃ Side Impact ┃
┃ Sensor ┃
┗━━━━━━┳━━━━━━━┛
┃ Ground
┃
Vehicle Chassis

Diagnostic Procedure

1. Read all stored SRS Diagnostic Trouble Codes.
2. Inspect the right front side impact sensor.
3. Check the connector for corrosion or loose terminals.
4. Test wiring continuity between the sensor and the Airbag Control Module.
5. Repair damaged wiring if necessary.
6. Replace the sensor if wiring tests normal.
7. Clear the DTC and verify that the warning light remains OFF.

Important Note

Wire colors, connector pinouts, sensor mounting locations, and circuit design vary between vehicle manufacturers and models. Always refer to the factory service manual before performing electrical tests on any SRS component.

Can You Drive With B0042?

The vehicle is generally still drivable, but the right-side airbag system may not operate correctly during an accident. This code should be repaired as soon as possible for maximum occupant protection.

Estimated Repair Cost

• Connector repair: $20–80
• Wiring repair: $40–150
• Impact sensor replacement: $80–300
• Airbag Control Module replacement (if required): $300–900

Related DTCs

• B0040
• B0041
• B0043
• B0044

Frequently Asked Questions

Can B0042 reset itself?

No. If the electrical fault remains, the code will return after being cleared.

Will the airbag deploy with B0042?

The affected side airbag may be disabled depending on the vehicle manufacturer and SRS strategy.

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OBDSpark Technician Tip: Never test airbag circuits with a test light or apply external voltage. Follow all manufacturer safety procedures before disconnecting or replacing SRS components.