Powertrain, generic · Vehicle speed, idle control and auxiliary inputs

P05AF Active Grille Air Shutter B Stuck On

Check engine lightOn

EmissionsRelevant

Drive cycleRequired

Limp modePossible

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. P05AF is the counterpart of P05AE: shutter B stuck open. Documented only in the VW group – Audi's 2022–24 A3, S3 and RS3 describe it internally as 'grille shutter 2 sticks open' and limit top speed to 100 mph on a shutter fault; the warning was sometimes set by engine module software. GM, Ford and Stellantis report everything under P05AE.

Likely causes

Engine module software (sporadic false message)

Louvres blocked open (ice, dirt, debris, accident damage)

Actuator or shutter unit B faulty

Poor supply or ground at the actuator

Symptoms

Check engine light on
Grille shutter warning, top speed limited (Audi)
Longer warm-up, slightly higher consumption

Repair estimate

DifficultyMediumWorkshop job

Parts and labour€0–500

Time0.3–2 h

Typical range across vehicles; the real cost depends on what the testing finds.

Parts involved

grille shutter bgrille shutter actuator bactuator wiringengine control module

Related codes

P05AE P05A0 P05B2 P05B0 P05B1

References: static.nhtsa.gov, static.nhtsa.gov, law.cornell.edu, static.nhtsa.gov.