B3475

Code

Generic B — Body

Seat Belt Pretensioner Circuit Fault

Brand: Generic

Type: B — Body

Views: UK: 14 EN: 12 RU: 12

AI status

Completed

ready

Completed 100%

Page language: EN

Causes

Open or short in pretensioner wiring harness
Corroded, loose or damaged pretensioner connector
Failed pretensioner (pyrotechnic device) with abnormal resistance
Faulty airbag/SRS control module or module connector
Damaged or worn clock spring (driver-side pretensioner)
Poor ground or supply to SRS module

Symptoms

SRS/airbag warning light illuminated on instrument cluster
Seat belt pretensioner may not activate in a crash
Related restraint system faults stored in airbag control module
Possible diagnostic trouble codes for other SRS components

What to check

Follow the vehicle manufacturer’s published SRS disable procedure (battery disconnect and specified wait time) before any physical work — pyrotechnic devices are hazardous
Scan airbag/SRS module to read freeze frame, fault status (active/stored) and any related SRS codes
Visually inspect pretensioner connector, harness, seat mounting area and routing for damage, corrosion or aftermarket splices
Check that all airbag/SRS module connectors and grounds are secure and corrosion-free
Measure resistance of pretensioner squib circuit with SRS system disabled and connectors disconnected (compare to spec)
Perform wiggle/insulation tests while monitoring resistance or live fault data to find intermittent faults

Signal parameters

Typical squib resistance at rest: usually low (approximately 0.5–3 ohms). Exact spec varies by vehicle — consult service manual
Open circuit: infinite/OL reading (indicates open wiring or connector) — fault expected
High resistance: significantly above spec (eg >5–10 ohms) indicates poor connection or internal device deterioration
Short to ground or battery: near 0 ohms between squib wire and ground or positive supply — indicates short
No normal DC voltage present at squib terminals when SRS is inactive; do NOT apply power to pyrotechnic devices

Diagnostic algorithm

Read and record all SRS DTCs and freeze-frame using a capable scan tool. Note whether B3475 is current or stored and any related codes.
Check service history for prior deployment or repairs to seats/SRS components.
Follow the manufacturer’s SRS safety isolation procedure (battery disconnect and required wait) before touching connectors or measuring squib resistance.
Visually inspect pretensioner connector(s), wiring harness, seat trim area and B-pillar for damage, corrosion, rodent chew or loose pins.
With SRS disabled and connectors disconnected at the pretensioner, measure resistance across the pretensioner squib pins and compare to factory specification. Replace component if outside spec.
Check continuity between pretensioner connector and airbag control module pin; check for short to ground or battery between the squib wires and chassis or 12V supply.
If driver-side, inspect and test clock spring for continuity and expected resistance; replace if faulty or intermittent.
Reconnect all connectors, clear codes with the scan tool, then perform SRS system self-test and verify that code does not return. If intermittent, perform wiggle tests under scan tool monitoring.
If wiring and connectors are good but fault remains, inspect airbag/SRS control module connectors and grounds; consider module fault if all else checks good. Follow manufacturer procedures for module replacement and configuration.
After repair, ensure any replaced pyrotechnic device is handled and disposed per safety rules and that the SRS system is reinitialized/configured as required.

Likely causes

Damaged connector or wiring at seat or B-pillar where harness flexes
High resistance or open in pretensioner squib circuit (most common)
Clock spring fault (driver side) creating intermittent contact
Corrosion at mating terminals after water ingress

Fault status

⚠️ Status

Seat belt pretensioner circuit fault — SRS warning lamp illuminated; fault stored in airbag control module. May be active or intermittent; repair required to restore pretensioner function.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 1-3 hours