B0301

Code

Generic B — Body

Airbag sensor circuit malfunction

Brand: Generic

Type: B — Body

Views: UK: 6 EN: 5 RU: 5

AI status

Completed

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Page language: EN

Causes

Damaged or chafed sensor wiring harness
Corroded, loose, or contaminated connector at the sensor or SRS module
Failed airbag/impact sensor
Short to power or ground in the sensor circuit
Faulty SRS control module or loss of module communication
Water intrusion or corrosion at sensor or connector

Symptoms

SRS / airbag warning lamp illuminated on dash
Possible disabling of airbag deployment for affected zone
Stored crash data or freeze-frame values in SRS module
Related occupant classification or seat belt reminder faults in some vehicles

What to check

Read SRS airbag codes and freeze frame with a capable scan tool
Visually inspect sensor(s), wiring harnesses, and connectors for damage, corrosion, or water entry
Check fuses and primary power/ground to SRS control module
Confirm vehicle battery is charged and charging system is healthy
Verify recent repairs or collision damage in the area of the failed sensor

Signal parameters

Reference supply: typically ~5 V supplied by the SRS control module (consult OEM spec)
Signal voltage: generally 0–5 V or a digital/pulsed signal; idle values vary by manufacturer — check live data with scan tool
Sensor resistance: often low (tens to hundreds of ohms); specific ohm values are manufacturer-specific
Circuit continuity: expect continuity between sensor connector and SRS module pin (near 0 ohms); open or short to ground/power indicates wiring fault

Diagnostic algorithm

Safety first: follow OEM SRS safety procedures. Disable the SRS system per manufacturer instructions before disconnecting or handling components (follow specified battery disconnect interval).
Retrieve all SRS codes and note freeze-frame or live-data values with a qualified scan tool; document initial conditions.
Perform a careful visual inspection of the suspect sensor, bracketry, and wiring; look for chafing, pinched sections, water damage, repair splice points, and connector corrosion.
Reconnect battery per OEM procedure (if required for live data), monitor live data while performing a wiggle test on wiring and connectors to reproduce the fault.
With ignition on, verify the sensor reference supply voltage and ground at the connector (using OEM-specified pinout and voltage expectations). Do not probe squib leads unless following OEM guidelines.
Measure continuity/resistance from the sensor connector to the SRS module pin to check for opens/shorts; repair any damaged wiring or poor grounds.
If wiring and connectors are good, compare sensor signal characteristics to OEM specifications. Replace the sensor if out of spec.
After repair or replacement, clear SRS codes, run SRS self-test with scan tool, and verify the airbag lamp extinguishes. Reinitialize/recalibrate occupant classification systems if required by manufacturer.
If the fault persists after sensor replacement and wiring repair, consider SRS control module diagnosis or replacement and check for software updates or known technical service bulletins.

Likely causes

Connector corrosion or poor mating at the sensor
Broken/chafed wiring between sensor and SRS module (common at seat/door hinge areas)
Failed airbag/impact sensor needing replacement
Intermittent connection detected by wiggle/torque tests

Fault status

⚠️ Status

Airbag sensor circuit malfunction detected. SRS warning lamp illuminated; possible sensor, wiring, connector, or module fault. Further diagnosis required.

🟡 Repair difficulty: Medium

⏱️ Diagnostic time: 0.5-2.0 hours