P05B6Active Grille Air Shutter B Supply Voltage Circuit Low
- Generic OBD-II code · Powertrain
- Turns on the check-engine light
- Matters for the ITP
- Needs a drive cycle to confirm a fix
- How the car detects it
- Shutter B is the second active grille shutter – at GM, Ford and Stellantis the lower one in the bumper. Shutters cut drag and speed warm-up when closed and open for cooling; CARB names them as an off-cycle CO2 technology and treats the actuator as an output component. Smart actuators report over LIN (loss of communication: U0285); a fault usually costs fuel and warm-up time, a closed shutter can make the engine run hot under load. P05B6 means the supply of actuator B is present but too low. Ford's 3.0 L diesel sets it at once when the actuator measures its internal supply below 6.9 V while system voltage is 9–16.26 V, from 5 s after start – pointing to a voltage drop in feed or ground or an internal fault.
- What you may notice
- Check engine light on
- Lower shutter inoperative at times
- Possibly further voltage codes or U0285
- Likely causes
- LikelyContact resistance in connector, wire or ground (corrosion)
- PossibleActuator faulty internally (measuring wrong)
- RareWeak battery or charging system
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Easy · Often possible to do yourself.Typical cost: €20 – €400
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.