Coolant Pump B Control Circuit / Open
The controller cannot drive the second electric coolant pump (B). Often used for aftertreatment, turbo cool-down, or hybrid battery loops — fault stops circulation in that loop.
Affected components
- Coolant pump b
- Pump relay
- Wiring harness
Common causes
- High likelihood: Open pump motor winding
- Medium likelihood: Broken control wire to the pump
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.