Air Bag Crash Sensor #2 Feed/Return Circuit Short To Ground
The airbag crash sensor #2 circuit is shorted to ground, meaning the electrical signal is leaking away like water through a hole in a pipe instead of reaching the airbag control module. This prevents the system from detecting collisions properly.
The airbag control module monitors the voltage signal from crash sensor #2 on its feed and return circuits. It expects a specific voltage range during normal operation; when the circuit shorts to ground, the voltage drops to near 0V, triggering a fault. The ECU continuously checks signal integrity and circuit resistance.
| Parameter | Normal Range | Fault Condition |
|---|---|---|
| Crash Sensor #2 Signal Voltage | 4.5–5.5 V | 0–1.0 V (short to ground detected) |
| Circuit Resistance | >10 kΩ | <5 kΩ (short condition) |
Code B1906 is a low-severity fault. Your vehicle is generally safe to drive to a workshop for diagnosis. However, do not ignore it indefinitely — low-severity codes often indicate developing problems that become expensive if neglected. Book a diagnostic appointment within 2–4 weeks. If you notice any additional symptoms (rough running, power loss, unusual smells), treat it as higher priority.
Once the fault is repaired, B1906 can be cleared using any OBD-II scanner. Connect the scanner, navigate to "Clear Codes" or "Erase DTCs," and confirm. The check engine light turns off immediately.
The code will return if the root cause was not actually fixed. The ECM re-detects the fault within 1–3 drive cycles and sets the code again.