P05B3Active Grille Air Shutter B Control Circuit High
- 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. P05B3 means the control circuit voltage of actuator B is too high – a control line shorted to positive or a driver unable to pull it to ground. In this family high comes before low. No manufacturer document available to us uses this code, like its shutter A counterpart. Ford reports coil shorts under P05B1, Toyota as P05B1 with failure type 12.
- What you may notice
- Check engine light on
- Lower shutter inoperative
- Slightly higher consumption, longer warm-up
- Likely causes
- LikelyActuator B faulty internally
- PossibleControl line shorted to positive (front harness)
- PossibleWater or corrosion in the connector
- RareModule driver
- Inspection (ITP)
- Matters for the ITP. While the check-engine light is on, the car fails the emissions check.
- Repair
- Medium · Often possible to do yourself.Typical cost: €80 – €450
- Related codes
Explanation from obdex (CC0), exactly as the app shows it. Guidance only; confirm with a workshop.