B0045 – Left Front Side Impact Sensor Circuit Open

DTC B0045 indicates that the Airbag Control Module (ACM) has detected an open circuit condition in the left front side impact sensor circuit. The sensor is part of the Supplemental Restraint System (SRS) and provides collision information required for proper airbag operation.

An open circuit means the electrical path between the sensor and the SRS module is interrupted, preventing normal communication.

Code Information

DTC: B0045
System: Supplemental Restraint System (SRS)
Description: Left Front Side Impact Sensor Circuit Open
Severity: High (Safety Related)

Symptoms

Airbag warning light ON.
SRS fault message displayed.
Side airbags may be disabled.
DTC B0045 stored in memory.
No engine performance issues.

Possible Causes

Broken wire inside the sensor harness.
Disconnected or loose sensor connector.
Corroded electrical terminals.
Damaged left front impact sensor.
Previous accident wiring damage.
Airbag Control Module fault (rare).

Typical Wiring Diagram

        🔴 B+ Power

             ┃

     ┏━━━━━━━━━━━━━━┓

     ┃  Airbag ECU  ┃

     ┗━━━━━━┳━━━━━━━┛

            ┃  🟡 Signal

            ╳  Open Circuit

     ┏━━━━━━┻━━━━━━━┓

     ┃ Left Front   ┃

     ┃ Impact Sensor┃

     ┗━━━━━━┳━━━━━━━┛

            ┃  ⚫ Ground

            ┃

        Vehicle Chassis

Diagnostic Procedure

Scan the vehicle and confirm DTC B0045.
Disconnect the battery and follow SRS safety procedures.
Inspect the left front impact sensor connector.
Check the wiring harness for cuts, breaks, or damage.
Test circuit continuity between the sensor and Airbag ECU.
Repair the open circuit or replace damaged components.
Clear the code and verify system operation.

Important Note

Connector design, wire colors, pin locations, and circuit values vary between vehicle manufacturers and models. Always use factory repair information before testing SRS circuits.

Can You Drive With B0045?

The vehicle may drive normally, but the airbag system may not function correctly during a collision. This fault should be repaired as soon as possible.

Estimated Repair Cost

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

Related DTCs

B0041
B0042
B0043
B0044

Frequently Asked Questions

What does an open circuit mean?

An open circuit means the electrical connection is interrupted, preventing current or data communication from reaching the sensor.

Can wiring damage cause B0045?

Yes. Broken wires and damaged connectors are among the most common causes of this code.

Should the sensor be replaced immediately?

First diagnose the wiring and connector. Replace the sensor only after confirming it is faulty.

OBDSpark Technician Tip: Airbag circuits require special safety procedures. Never use a test light or apply external voltage to SRS wiring.

OBD Spark

B0045 – Left Front Side Impact Sensor Circuit Open