What Does B1931 Mean?
This code indicates the airbag control module has detected an electrical fault in the feed or return circuit of the primary crash sensor (accelerometer/impact sensor #1). The airbag control module continuously monitors the crash sensor circuits for proper voltage, resistance, and signal integrity. When an open circuit, short to ground, short to power, or excessive resistance is detected in the sensor's power supply or ground return path, this code is set and the airbag warning light illuminates.
Safety Warning
This is a critical safety concern as the airbag system is disabled and airbags will NOT deploy in a crash, leaving occupants unprotected. Vehicle should not be driven until repaired, and this repair requires specialized airbag system knowledge to avoid accidental deployment or further damage.
Common Causes
45%
Damaged wiring harness or corroded connections at crash sensor #1 connector, often from front-end collision damage, water intrusion, or connector terminal corrosion
30%
Failed frontal crash sensor #1 due to internal component failure or previous impact damage
15%
Poor ground connection or broken ground wire in the airbag sensor circuit
10%
Airbag control module internal circuit failure affecting crash sensor monitoring circuit
Diagnostic Steps
1
Step 1: Perform visual inspection of crash sensor #1 location (typically mounted in front bumper reinforcement or radiator support) for physical damage, water intrusion, connector damage, or previous collision repair evidence
2
Step 2: Disconnect crash sensor #1 connector and inspect for corrosion, pushed-back pins, or moisture; clean connector with electrical contact cleaner if corrosion present and retest
3
Step 3: With sensor disconnected, use digital multimeter to check continuity and resistance of sensor feed and return circuits from sensor connector back to airbag control module connector (consult wiring diagram for pin identification); should show 0-5 ohms resistance with no shorts to ground or power
4
Step 4: Measure voltage at crash sensor connector feed wire with ignition ON; should show battery voltage or specified reference voltage (typically 5V or 12V depending on manufacturer)
5
Step 5: If wiring and power/ground circuits test normal, check resistance across crash sensor terminals per manufacturer specifications (typically 1-10k ohms); replace sensor if out of range or if resistance is infinite/zero
6
Step 6: Clear codes, perform airbag system self-test using scan tool, and verify repair by driving vehicle through various conditions; airbag light should remain off and no codes should return
Estimated Repair Cost
$200 - $1,200
Parts + labor, varies by vehicle and location
This code indicates the airbag control module has detected an electrical fault in the feed or return circuit of the primary crash sensor (accelerometer/impact sensor #1). The airbag control module continuously monitors the crash sensor circuits for proper voltage, resistance, and signal integrity. W...
The most common cause of B1931 (Air Bag Crash Sensor #1 Feed/Return Circuit Failure) is: Damaged wiring harness or corroded connections at crash sensor #1 connector, often from front-end collision damage, water intrusion, or connector terminal corrosion
Typical repair costs for B1931 range from $200 to $1,200, depending on the vehicle, location, and whether you do it yourself or go to a shop.
This is a critical safety concern as the airbag system is disabled and airbags will NOT deploy in a crash, leaving occupants unprotected. Vehicle should not be driven until repaired, and this repair requires specialized airbag system knowledge to avoid accidental deployment or further damage.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1931 to identify the root cause.
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Quick Info
Category
Body
System
Supplemental Restraint System (SRS/Airbag)
Difficulty
Type
Manufacturer
Recommended Tools
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