Brake System Control Module B Requested MIL Illumination
A second brake system control module (typically the redundant secondary unit on by-wire or AV-grade brake systems) has signalled an emissions-relevant fault and requested the engine controller to switch on the MIL.
Affected components
- Brake control module b
- Communication bus
Common causes
- High likelihood: Active DTC stored in the secondary brake module
- Low likelihood: Communication loss interpreted as MIL request
Diagnostic notes
- The malfunction indicator lamp may illuminate
Related codes
Sources
Diagnostic information is provided for reference only. Confirm the code with a compatible scan tool and follow the vehicle manufacturer's service procedures before replacing components.