Squib – Function, Symptoms, Types, Diagnosis, and Possible DTCs

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Squib – Function, Symptoms, Types, Diagnosis, and Possible DTCs

The Squib is the electrical igniter inside an airbag module or seat belt pretensioner. When the Airbag Control Module (ACM/RCM/SDM/ORC) detects a severe collision, it sends a precisely controlled electrical current to the squib. The squib ignites the inflator, causing the airbag to deploy or the pretensioner to activate within milliseconds.

What Is a Squib?

Squib = Airbag / Pretensioner Electrical Igniter

Main Functions

  • Receives the deployment signal from the SRS control module.
  • Ignites the airbag inflator.
  • Activates the seat belt pretensioner.
  • Operates only during a qualifying collision.

Types of Squibs

  • Driver Airbag Squib
  • Passenger Airbag Squib
  • Side Airbag Squib
  • Curtain Airbag Squib
  • Knee Airbag Squib
  • Seat Belt Pretensioner Squib

Simple Circuit Diagram

+----------------------+
| Airbag Control Module|
+----------------------+
          │
   Deployment Signal
          │
          ▼
+----------------------+
|       Squib          |
+----------------------+
          │
          ▼
 Airbag Inflator
 Pretensioner

Common Symptoms of a Fault

  • Airbag warning light ON.
  • Open circuit or short circuit DTCs.
  • High or low deployment loop resistance.
  • SRS system disabled.

Possible Diagnostic Trouble Codes (DTCs)

  • B0010–B0015 – Driver Airbag Squib Circuit
  • B0020–B0028 – Passenger Airbag Squib Circuit
  • B0030–B0040 – Pretensioner Squib Circuit
  • B0051–B0053 – Deployment Loop Fault
  • Manufacturer-specific Squib DTCs

Diagnosis Tips

  • Read SRS codes using a professional scan tool.
  • Inspect connectors and wiring for damage.
  • Check the clockspring if the driver airbag squib is affected.
  • Never apply battery voltage directly to a squib.
  • Follow the manufacturer's approved SRS testing procedures.

Important Safety Note

A squib is a pyrotechnic device and can deploy an airbag or pretensioner if handled incorrectly. Never measure squib resistance directly with a standard multimeter unless the manufacturer specifically allows it. Always disconnect the battery and wait the recommended time before servicing any SRS component.

Frequently Asked Questions

What does a squib do?

It converts the electrical deployment signal into the ignition needed to activate the airbag inflator or seat belt pretensioner.

Can a faulty squib turn on the airbag warning light?

Yes. An open circuit, short circuit, or abnormal resistance in the squib circuit commonly triggers the SRS warning light.

Can a squib be repaired?

No. Squibs are not repairable. If defective or deployed, the affected airbag module or pretensioner must be replaced.

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