What it means
Active Grille Air Shutter B Position Sensor Circuit: an electrical fault is present in the circuit. Active grille shutters manage airflow for engine cooling and aerodynamics.
At a glance
- Usually lights the check-engine light
How it works
Active grille shutter B has a position sensor that reports how far that shutter has moved, while the shutters regulate cooling airflow and aerodynamic drag. The control module sets P05A9 when it detects an electrical fault in shutter B's position-sensor circuit, so it may not be able to confirm or command the shutter's position.
Common causes
Most likely first.
- Open or short in position sensor wiring
- Failed shutter position sensor
- Loose or corroded connector
Symptoms
- Check-engine light
- Active grille shutters may not move as commanded
- Cooling fan may run more often
How to diagnose it
- Use a scan tool to read freeze-frame data and compare commanded shutter B movement with its reported position.
- Inspect shutter B's sensor connector and wiring for looseness, corrosion, water ingress, broken insulation, or damaged terminals.
- Check whether the position reading changes as shutter B is commanded to move, and note any dropouts or fixed readings.
- Test the sensor circuit for opens or shorts and check its connections against the manufacturer's wiring information.
- If the circuit is sound, test shutter B's position sensor and actuator separately according to the vehicle's service information.
Common fixes
- Reconnect and secure shutter B's loose sensor connector.
- Clean corroded terminals and repair damaged connector seals.
- Repair an open or short in the position-sensor wiring.
- Replace shutter B's position sensor or actuator if testing confirms it has failed.
Can I keep driving?
You can usually drive cautiously if engine temperature stays normal, but the vehicle may not manage cooling airflow correctly and the fan may run more often. Watch the temperature gauge and stop if the engine overheats.
A code shows where the control module detected a fault, not always which part failed. Check the causes in order and confirm with a test before replacing parts. Have several codes? Check them together
This is a generic code: it means the same on every make. The car’s maker may add more detail in its own service information.