B1001
SDM (Airbag Module) Option Configuration Error
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Code B1001 is a General Motors manufacturer-specific code indicating that the Sensing and Diagnostic Module (SDM)—the airbag control unit—has a configuration mismatch with the Body Control Module (BCM). When you turn on the ignition, the SDM transmits a 4-digit option configuration key to the BCM. If the BCM's stored value doesn't match, B1001 is set and the airbag warning light illuminates.
This code most commonly appears after parts have been replaced—such as the SDM, BCM, or even the instrument cluster—without proper reprogramming. It can also occur if a salvage-yard SDM with a different configuration was installed. The vehicle will drive normally, but the supplemental restraint system (airbags) may be partially or fully disabled, which is a serious safety concern.
Do not ignore this code. While the car will drive fine, your airbags may not deploy in an accident. The fix usually involves having a dealer or qualified shop use a factory scan tool (like GM's Tech2 or MDI) to reprogram the BCM with the correct SDM option code. If the wrong SDM is installed, the correct unit must be sourced. Professional diagnosis and repair typically costs $100–$600 depending on whether reprogramming or module replacement is required.
Severity
Symptoms
- •Airbag warning light illuminated on dashboard
- •Check engine or service indicator light on
- •Possible horn malfunction
- •Cruise control may be disabled
- •No visible drivability symptoms but safety systems compromised
- •SRS system may not deploy properly in a collision
Likely Causes
When the Sensing and Diagnostic Module (SDM) or Body Control Module (BCM) is replaced, the configuration data must be synchronized. If the BCM was not reprogrammed with the correct SDM option code, this mismatch triggers B1001.
If the wrong part number SDM was installed—common after a used-parts repair—the stored 4-digit configuration key will not match what the BCM expects, triggering this code.
Damaged, corroded, or loose connectors in the data lines between the SDM and BCM can cause communication errors that prevent proper configuration verification.
Internal failures in either the SDM or BCM can corrupt stored configuration data, causing the modules to report a mismatch even when the correct parts are installed.
Estimated Cost
Professional Repair
Includes parts + labor
Common Fixes
- Have the BCM reprogrammed with correct SDM configuration at a dealer
- Verify the SDM part number matches the vehicle application
- Inspect and repair wiring between the SDM and BCM
- Replace the SDM or BCM if found defective
- Clear codes and verify the airbag light turns off after repair