P05A4Active Grille Air Shutter A 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
- An active grille shutter closes louvres in the grille to cut drag and speed warm-up and opens them for cooling; CARB names it as an off-cycle CO2 technology and treats the actuator as an output component. Smart actuators (Ford 3.0 L diesel, Toyota) check their own coil and supply and report over LIN; simpler ones (VW 1.8 T) have their own supply and a control line from the engine module. GM uses none of P05A2–P05A8. A fault usually only costs fuel and warm-up time. P05A4 means the control circuit voltage 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. Ford reports coil shorts under P05A2, Toyota with a failure-type byte.
- What you may notice
- Check engine light on
- Shutter not moving (usually open)
- Slightly higher consumption, longer warm-up
- Likely causes
- LikelyActuator motor faulty internally
- PossibleControl line shorted to positive (front harness)
- PossibleWater or corrosion in the connector
- RareEngine module 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.