P05AA

What it means

P05AA means the control unit has found that the position signal from active grille air shutter 'B' is implausible or does not match what it commanded. The shutters open and close to manage engine cooling, air conditioning load and aerodynamics. The code sets when the reported position drifts out of the expected range, does not follow the commanded position, or the shutter does not move properly. Which shutter set is 'B' and which module controls it depends on the vehicle.

Symptoms

• Warning light on, with an engine or cooling system message on some models
• Engine or coolant temperature running higher than normal in traffic or at high load
• Reduced air conditioning performance
• Slightly worse fuel economy at motorway speed
• Rattling, clicking or buzzing from the front of the car as the actuator tries to move
• Shutters visibly stuck open or closed

Possible causes

• Shutter vanes or linkage jammed by road debris, ice, dirt or a damaged bumper coverlikely
• Faulty shutter actuator or its built-in position sensorlikely
• Broken or seized linkage, worn gears or broken vane clips in the shutter assemblypossible
• Damaged wiring, corroded connector or poor earth or supply to the actuatorpossible
• Front-end collision damage or a misaligned shutter assemblypossible
• Fault in the controlling module or outdated software (model-specific)rare

How to diagnose

1. Read all stored and pending codes and the freeze frame data, noting coolant temperature, vehicle speed and ambient temperature when the code set
2. Look at the grille shutters for debris, ice, damage or loose parts, and move the vanes by hand (where safe) to check for binding
3. Inspect the actuator wiring and connector for chafing, water ingress, corrosion and pushed-back pins
4. Use a scan tool's actuator test or live data to command the shutters and compare commanded and actual position
5. Check the actuator supply, earth and signal circuits against the manufacturer's wiring data
6. Check the actuator position sensor signal for smooth, plausible travel through the full range
7. Check for related cooling system or air conditioning codes, and for technical bulletins or software updates for the model
8. Clear the code after repair and road test to confirm it does not return

How to fix

• Clear debris and free any jammed vanes, and repair or replace damaged shutter parts
• Replace the shutter actuator or assembly if the motor or position sensor is faulty
• Repair damaged wiring, terminals or connectors, and restore good supply and earth
• Repair or realign the front-end structure or bumper mounting if collision damage is affecting the shutters
• Perform any required shutter relearn or adaptation after replacement, following the manufacturer's procedure
• Update the control module software only if an outdated calibration is a known cause for that model

Can I keep driving?

Nearby codes

• P05A9GenericActive Grille Air Shutter B Position Sensor Circuit
• P05ABGenericActive Grille Air Shutter B Position Sensor Circuit High