B004C

Code

Generic B — Body

SRS airbag squib circuit fault

Brand: Generic

Type: B — Body

Views: UK: 20 EN: 41 RU: 12

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Page language: EN

Causes

Open circuit in squib wiring (broken conductor, disconnected connector)
Short to ground in squib wiring
Short to battery/ignition power in squib wiring
High resistance at connector or in squib (corrosion, loose terminal)
Faulty squib (airbag inflator harness) or seatbelt pretensioner
Faulty clockspring (steering wheel airbag circuits)

Symptoms

SRS/Airbag warning lamp illuminated or flashing
Multiple or additional SRS-related DTCs stored
Possible deactivation of affected airbag/pretensioner circuit(s)
Vehicle may fail safety inspection due to SRS warning
No other drivability symptoms (engine runs normally)

What to check

Read and record all SRS DTCs and freeze-frame data with an appropriate scan tool
Record ignition and battery voltage before testing; ensure battery charged
Follow manufacturer safety procedures: disable SRS system by disconnecting battery and wait the required time before touching airbag circuits
Visually inspect airbag connectors, harness routing, and common wear points (steering column, door hinges, seat tracks)
Inspect clockspring (driver-side) for damage if relevant
Check for water damage or corrosion in connectors and modules

Signal parameters

Typical squib resistance (cold, at connector with battery disconnected): ~2–3 ohms for most driver/passenger frontal squibs (consult vehicle spec)
Open-circuit: infinite/OL (no continuity) — indicates break/disconnected squib
Short-to-power: very low resistance to battery voltage path or near 0 ohms between squib and battery power source (vehicle-specific)
Short-to-ground: near 0 ohms between squib circuit and ground
Scan-tool SRS data: module reports circuit status (open/short/high resistance) and may show which circuit/pin

Diagnostic algorithm

Use an OEM-capable scan tool to read all SRS codes and note the specific circuit flagged. Check for related codes (clock spring, seatbelt pretensioner, module faults).
Follow safety procedure: switch ignition off, disconnect negative battery terminal, and wait the manufacturer-specified time (commonly 2–10 minutes) before touching SRS wiring or components. Wear proper PPE.
Visually inspect the suspect circuit connectors, pins and wiring for corrosion, bent pins, heat damage, or water intrusion. Repair any obvious connector damage.
With battery still disconnected, measure squib continuity/resistance at the airbag connector or service connector per OEM procedure. Compare to factory spec (typically ~2–3 Ω). Note open or out-of-range values.
If resistance is out of specification, isolate harness sections and re-measure to locate open/short (disconnect connectors sequentially to find where reading changes).
Pay special attention to steering column/clock spring (driver-side) and seat harnesses (passenger/side airbags). Perform wiggle tests while monitoring resistance for intermittent faults (battery disconnected between tests).
Repair or replace damaged wiring, connectors, clockspring, or squib module as required. Use only OEM or approved replacement parts. Replace airbag modules only if specified or if deployed/damaged.
After repairs, reconnect battery, use scan tool to clear codes, and run SRS system self-tests per manufacturer instructions. Confirm no DTCs return and that SRS lamp extinguishes.
If fault persists after harness and component replacement, consult service manual for SRS control module diagnostics; replace module only if supported by diagnostic flow and security/locking procedures.

Likely causes

Damaged/loose airbag connector or terminal
Worn or broken clock spring (driver-side)
Corroded or pinched harness at door hinge, seat base, or under-seat
Failed squib (airbag module or pretensioner)
Short to ground on a harness near a body panel or connector

Fault status

⚠️ Status

Stored DTC B004C — SRS airbag squib circuit fault. The airbag control module detected abnormal/open/short/high-resistance condition in a squib firing circuit. SRS warning lamp will be on and affected airbag circuit may be disabled.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1.0-3.0 hours