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So I had this code pop up. At first I was pissed because I've only owned the car a week. Scanned it and found out it's for the active grille shutters.

There had just been freezing rain so I'm assuming they got stuck open.

My question is does anyone know the parameters for those things to open and close?

I'm going to go to the car wash and spray them with some hot water and blow them dry but I'd like to know what position they are supposed to be in and when So I can diagnose the issue if it happens again.

Thanks!
 

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Generally closed ambient below 50f.
Generally closed at speeds above 50mph in warm weather.......ecm determines airflow needs for cooling system and a/c condenser performance and continually adjusts.
For the most part, open fully at lower speeds when above 50f.

I agree with your first thoughts.....ice bound at the hinges.

Rob
 

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I just got this code right after a freezing rain along with a P018B. Cleared the codes the next day and has not recodeded for over a week.

What is a grille shutter and how could freezing rain affect it?

Any help would be appreciated


******update****. I did more search and read all about it. Next time I will research more before asking. Thanks
 

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My car just threw that code. I checked the shutters with my scan tool. They fully close and only open a crack when commanded.

Not freezing and no physical damage.

I had a 2017 Volt a couple years ago. First day of ownership brand new off the lot it threw this same code. The Volt had a batch of bad shutter assemblies.

Debating on pulling my bumper and seeing if sand / grit is causing them not to open or just drop it off at the stealer.
 

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I have the ECO with the active grille shutter and since the beginning I wanted to monitor and understand how it works. I put a mercury switch on it and connected to a blue LED inside. When the LED is on, the grille is fully opened. The computer drives everything, depending of driving conditions, speed, coolant temperature. The basic behavior is:
1. Temperature under 40-42F, the grille stays at the last position. That mean if it was opened it will stay open, if closed, closed, etc. It won't even try to move although sometimes there is no ice to lock it, etc. This is a safety feature so it will not be damaged.
2. If you drive over ~40MPH the grille closes. IF condition 1 is not in place, IF the coolant temperature is not "too high", IF computer analyses all the parameters and he "agrees" to open it!
3. If the outside temperature is over 100 (my observations) also the grille will have the tendency to stay open. On my ECO this is related also with the smart thermostat that computer can open electronically even otherwise the thermostat will open by itself mechanically.

During the 8 years with my first Cruze I never had an issue with it, I just learned how it behaves. Never saw its advantage, the 0.5MPG they advertised I can get by only changing the driving style.

This is for gas, but it may be similar for Diesel:

"From the service manual:

Active Grille Air Shutter Description and Operation
The active grille air shutter actuator closes louvers at the front bumper to enhance vehicle aerodynamics in driving situations where cooling and A/C loads are relatively low and high levels of front end airflow are not required. If high levels of airflow are required the active grille air shutter actuator opens the louvers. The control signal from the fuel pump control module, ignition and ground circuits enable the active grille air shutter actuator to operate. If the conditions for opening the louvers are reached the fuel pump control module commands the active grille air shutter actuator to open the louvers.

The single active grille air shutter system consists of an individual motor operated mechanism hinged behind the vehicle front grille for controlling the amount of air entering the engine compartment. It includes three wires, ground, power and pulse width modulated signal to the actuator. The fuel pump control module determines shutter state based on various vehicle conditions such as vehicle speed, coolant temperature, fan state, refrigerant system pressure, A/C compressor state and ambient temperature. The pulsed signal controlling the shutter mechanism will be able to control the shutter to close/open positions.

The actuator is powered by an ignition circuit that is active when the key is in the RUN position. The vehicle may have to be driven for up to 13 minutes at speeds greater than 41 kph (25 mph) before the shutter begins to move. If low ambient temperature is detected, the shutter will remain in the closed position."
 
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