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.
Medium severity. Can I keep driving?If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
Symptoms
- Check engine light on
- Shutter not opening: engine temperature rises in traffic, fan running often
- Often after frost, gone after thawing
Most likely causes
- Louvres blocked by ice, snow or debris
- Bent bracket or bumper part blocking the louvres
- Actuator, gear or shaft faulty (shutter stays closed)
- Louvres unhooked or rubbing on horn or intake duct
- Calibration or software
What to check, in order
Start with the simplest. You can tick off each step.
Good to know
- Repair difficulty: medium
- It affects emissions.
What each character of P059F means
- P: Powertrain: engine and transmission
- 0: Generic code: same on every make
- 5: Speed and idle
- 9F: Specific fault in that system
Frequently asked questions
Can I keep driving with code P059F?
If the car is running normally, drive in moderation to a repair shop. If it loses power or another warning appears, do not continue.
What causes code P059F?
The most common causes are: louvres blocked by ice, snow or debris; bent bracket or bumper part blocking the louvres; actuator, gear or shaft faulty (shutter stays closed).
Related codes
- P05A0Active Grille Air Shutter A Stuck On
- P05A1Active Grille Air Shutter A Position Sensor Minimum/Maximum Stop Performance
- P05A2Active Grille Air Shutter A Control Circuit/Open
- P05AEActive Grille Air Shutter B Performance/Stuck Off
- P059BActive Grille Air Shutter A Position Sensor Circuit Range/Performance
Sources
- gsi.ext.gm.com: 18OBDG03A Engine Diagnostics
- gsi.ext.gm.com: 14OBDG04 Engine Diagnostics
- fordservicecontent.com: obd summary diesel 2023
- static.nhtsa.gov: MC 10246454 0001
Values and procedures vary by manufacturer. If it affects brakes, steering, fuel or high voltage, see a professional. Updated: 2026-11-04. How we build these pages.