P059F: Active Grille Air Shutter A Performance/Stuck Off

What does P059F mean?

The active grille shutter (A = upper or only shutter, B = second) closes louvres to cut drag and speed warm-up and opens them for cooling; CARB names it as an off-cycle CO2 technology and requires its components to be monitored. P059F compares commanded and reached position. GM checks it in two stages – detection, then five clearing attempts – type B, two trips; Ford's 3.0 L diesel at over 6° deviation in operation or 20° when learning fully open. 'Stuck off' means stuck closed at Toyota (failure type 73) and Nissan; GM and Ford use P059F for any deviation. Typical are ice, snow, debris or a bent bracket – a closed shutter can make the engine run hot in traffic.

The code tells you which monitor failed, not which part is broken. Test before replacing parts.

Symptoms

• Check engine light on
• Shutter not opening: engine temperature rises in traffic, fan running often
• Often after frost, gone after thawing

Common causes

• High Louvres blocked by ice, snow or debris
• Medium Bent bracket or bumper part blocking the louvres
• Medium Actuator, gear or shaft faulty (shutter stays closed)
• Medium Louvres unhooked or rubbing on horn or intake duct
• Low Calibration or software

Likelihood is a general estimate across vehicles; your make and model may differ.