B1102

Symptoms

• Airbag (SRS) warning light on - often the only symptom
• airbags and seatbelt pre-tensioners are disabled and will not deploy in a collision while the code is active. If low system voltage is the root cause: slow engine cranking (especially in cold weather)
• dimming or flickering lights
• and possibly multiple simultaneous warning lights (ABS, traction control) from other modules losing voltage.

Probable causes

• Weak or dying 12V battery (reported as the most common cause)
• failing alternator causing system-wide low voltage
• poor electrical connections or corroded/damaged wiring in the SRS module power supply circuit
• faulty airbag control module.

Diagnostic steps

1. Read the code with an SRS-capable scan tool and note whether it is current or history.
2. Test the 12V battery and charging system first - a weak battery is the most likely cause; replace the battery or repair the charging system if out of spec.
3. Inspect the SRS module power and ground circuit wiring and connectors for corrosion, looseness or damage; repair as needed.
4. With supply voltage restored to normal, clear the code using the SRS-compatible scanner - disconnecting the battery will not clear B1102; on some vehicles the SRS ECU erases the code on its own once supply voltage returns to normal.
5. If the code resets with a healthy battery, charging system and wiring, suspect the airbag control module. Treat as urgent: the restraint system is inoperative while the code is active.