Vacuum Pump Control Circuit A/Open
The control circuit driving the electric vacuum pump (used to maintain brake-booster vacuum on direct-injection or hybrid powertrains where the engine is not always running) is open. The ECM cannot run the pump on demand — booster vacuum drops, pedal feel hardens, brake assist may be reduced.
Affected components
- Vacuum pump
- Wiring harness
Common causes
- High likelihood: Open control wire to the pump
- Medium likelihood: Failed driver in the control module
Diagnostic notes
- The malfunction indicator lamp may illuminate
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.