What Does B1945 Mean?
This code indicates that the airbag control module has detected an open circuit in the ground path for crash sensor #2. The airbag system continuously monitors the integrity of all crash sensor circuits to ensure proper deployment capability. An open ground circuit prevents the sensor from functioning correctly and disables the airbag system's ability to detect impacts in that specific zone.
Safety Warning
The vehicle should not be driven as the airbag system is disabled or significantly compromised. In the event of a collision, airbags may not deploy properly, creating severe injury risk to occupants. This requires immediate repair before operating the vehicle.
Common Causes
45%
Damaged or corroded wiring harness or connector at crash sensor #2 ground circuit
30%
Faulty crash sensor #2 with internal ground circuit failure
15%
Poor ground connection at chassis ground point or broken ground strap
10%
Airbag control module internal fault or connector corrosion
Diagnostic Steps
1
Step 1: Perform visual inspection of crash sensor #2 (typically located in front bumper reinforcement or side impact zone) and its connector for physical damage, corrosion, water intrusion, or loose connections. Check connector pins for backing out, corrosion, or bent terminals.
2
Step 2: Using a digital multimeter, verify ground circuit continuity from crash sensor #2 connector (sensor disconnected) to chassis ground. Resistance should be less than 1 ohm. Also check for continuity from sensor ground pin back to airbag control module ground circuit.
3
Step 3: Inspect chassis ground point associated with airbag system for corrosion, paint contamination, loose mounting bolt, or broken ground strap. Clean ground connection and verify metal-to-metal contact with resistance test.
4
Step 4: With sensor reconnected and ignition on, use multimeter to backprobe the ground circuit at the sensor connector while monitoring voltage. Should read 0 volts or very close to battery negative. If voltage present, trace wiring for open circuit.
5
Step 5: If all wiring and grounds test good, replace crash sensor #2 and verify repair by clearing codes and performing airbag system self-test. Monitor for code recurrence after test drive including moderate bumps.
6
Step 6: If code persists after sensor replacement and all wiring checks pass, suspect airbag control module internal fault and verify all ACM connector terminals are clean and properly seated before module replacement.
Estimated Repair Cost
$150 - $800
Parts + labor, varies by vehicle and location
This code indicates that the airbag control module has detected an open circuit in the ground path for crash sensor #2. The airbag system continuously monitors the integrity of all crash sensor circuits to ensure proper deployment capability. An open ground circuit prevents the sensor from functioni...
The most common cause of B1945 (Air Bag Crash Sensor #2 Ground Circuit Open) is: Damaged or corroded wiring harness or connector at crash sensor #2 ground circuit
Typical repair costs for B1945 range from $150 to $800, depending on the vehicle, location, and whether you do it yourself or go to a shop.
The vehicle should not be driven as the airbag system is disabled or significantly compromised. In the event of a collision, airbags may not deploy properly, creating severe injury risk to occupants. This requires immediate repair before operating the vehicle.
Start by connecting an OBD2 scanner to read the code and any freeze frame data. Then follow the diagnostic steps specific to B1945 to identify the root cause.
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Quick Info
Category
Body
System
Supplemental Restraint System (SRS/Airbag)
Difficulty
Type
Manufacturer
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