2017 Nissan Altima Active Grille Shutter

Okay, let's dive into the Active Grille Shutter (AGS) system on the 2017 Nissan Altima. It's a seemingly simple system, but it plays a key role in improving fuel economy and reducing aerodynamic drag. This isn't some fancy race car modification; it's a factory-installed component, but understanding how it works can help you troubleshoot potential issues and appreciate its contribution to overall vehicle efficiency.

What is an Active Grille Shutter?

Simply put, an Active Grille Shutter is a set of electronically controlled louvers located behind the front grille of your Altima. These louvers open and close based on various engine operating parameters, modulating the airflow to the engine compartment. The goal is to minimize drag and optimize engine temperature.

Think of it like this: when your engine is cold, the AGS system will typically keep the louvers closed. This allows the engine to warm up faster, which improves fuel economy and reduces emissions during the initial stages of driving. Once the engine reaches its optimal operating temperature, the AGS will open the louvers to allow for proper cooling. At higher speeds, the system prioritizes aerodynamics and may partially or fully close the louvers to reduce drag, even if the engine is at operating temperature. This is a crucial aspect of its fuel-saving functionality.

Components of the AGS System

The AGS system consists of several key components that work together:

Grille Shutter Assembly: This is the physical assembly of louvers positioned behind the grille. They are usually made of plastic to reduce weight and cost.
Actuator Motor: This electric motor is responsible for opening and closing the louvers. It receives commands from the Engine Control Module (ECM) and precisely positions the louvers accordingly. This actuator is usually a stepper motor, allowing for precise, incremental movement.
Position Sensor: The position sensor provides feedback to the ECM regarding the position of the louvers. This is critical for ensuring that the louvers are opening and closing as intended. This sensor is often integrated into the actuator motor assembly.
Engine Control Module (ECM): The ECM, the car's central computer, is the brain of the AGS system. It monitors various engine parameters, such as engine coolant temperature (ECT), vehicle speed, ambient air temperature, and air conditioning system status, and uses this information to determine the optimal position of the louvers.
Wiring Harness: This connects all the components of the AGS system to each other and to the vehicle's electrical system.

How the AGS System Works: A Deep Dive

Let's break down the operation of the AGS system in more detail:

Data Acquisition: The ECM continuously monitors a range of sensors, including the ECT sensor, vehicle speed sensor (VSS), ambient air temperature sensor, and AC pressure sensor. These sensors provide the ECM with real-time information about the engine's operating conditions and the surrounding environment.
Logic Processing: The ECM uses a pre-programmed algorithm to determine the optimal position of the grille shutters based on the sensor data. This algorithm takes into account factors such as engine temperature, vehicle speed, aerodynamic drag, and the need for cooling. The algorithm is often complex and may involve lookup tables or mathematical models.
Command Signal: Based on the algorithm's output, the ECM sends a command signal to the actuator motor. This signal specifies the desired position of the louvers, ranging from fully closed to fully open, or somewhere in between. The signal is typically a Pulse Width Modulation (PWM) signal, which allows the ECM to precisely control the speed and direction of the motor.
Actuation: The actuator motor receives the command signal and moves the louvers to the commanded position. The motor is usually geared to provide sufficient torque to overcome the resistance of the louvers and any debris that may be obstructing their movement.
Feedback and Control: The position sensor provides feedback to the ECM regarding the actual position of the louvers. The ECM compares the actual position to the commanded position and makes adjustments as needed to ensure that the louvers are in the correct position. This feedback loop is essential for maintaining accurate control of the AGS system.

The ECM uses closed-loop control, meaning it actively monitors the system's performance and makes adjustments to maintain the desired output. This is crucial for adapting to changing driving conditions and ensuring optimal fuel economy and engine performance.

Troubleshooting AGS Problems

While the AGS is a relatively simple system, problems can arise. Here are some common issues and how to diagnose them:

Common Problems:

Stuck Louvers: The louvers may become stuck in either the open or closed position due to debris, corrosion, or damage. This can lead to overheating (if stuck closed) or reduced fuel economy (if stuck open).
Actuator Motor Failure: The actuator motor may fail due to electrical problems, mechanical wear, or corrosion. This will prevent the louvers from opening and closing properly.
Position Sensor Failure: A faulty position sensor can provide incorrect feedback to the ECM, causing the louvers to operate erratically or not at all.
Wiring Issues: Damaged or corroded wiring can disrupt the communication between the ECM and the AGS components.
ECM Issues: In rare cases, the ECM itself may be the source of the problem.

Diagnostic Steps:

Visual Inspection: Start by visually inspecting the grille shutter assembly for any obvious signs of damage or debris. Look for broken louvers, loose connections, or corrosion.
Scan for Diagnostic Trouble Codes (DTCs): Use an OBD-II scanner to check for any DTCs related to the AGS system. Common codes might include those related to actuator motor performance, position sensor signal, or circuit faults. Some example DTCs could be:
- P059F - Active Grille Air Shutter Performance
- B2615 - Active Grille Shutter Motor Circuit
- B2616 - Active Grille Shutter Position Sensor Circuit
Actuator Motor Testing: If you suspect a faulty actuator motor, you can test it using a multimeter. Disconnect the motor connector and check for voltage and ground. You can also try applying voltage directly to the motor to see if it operates. Be careful when applying voltage directly, as incorrect polarity or voltage can damage the motor. Refer to the service manual for the correct wiring diagram and voltage specifications.
Position Sensor Testing: The position sensor can be tested using a multimeter to measure its resistance or voltage output. The specific testing procedure will vary depending on the type of sensor. Again, refer to the service manual for the correct procedure and specifications.
Wiring Inspection: Inspect the wiring harness for any signs of damage, corrosion, or loose connections. Use a multimeter to check for continuity between the various components.

Repairing or Replacing the AGS System

Once you've identified the problem, you can proceed with the repair. Depending on the issue, you may be able to repair the AGS system or you may need to replace the faulty component. Here's a quick overview:

Cleaning and Lubrication: If the louvers are stuck due to debris or corrosion, you may be able to clean and lubricate them to restore their proper function. Use a non-corrosive cleaner and a silicone-based lubricant.
Actuator Motor Replacement: If the actuator motor is faulty, it will need to be replaced. The replacement procedure will vary depending on the vehicle, but it typically involves removing the grille and the old actuator motor, and then installing the new motor.
Position Sensor Replacement: If the position sensor is faulty, it will also need to be replaced. The replacement procedure will vary depending on the vehicle, but it often involves replacing the entire actuator motor assembly as the sensor is commonly integrated.
Wiring Repair: If the wiring is damaged, you can repair it by splicing in new wires or replacing the entire wiring harness. Ensure you use proper splicing techniques and waterproof connectors to prevent future problems.
Component Replacement: If the grille shutter assembly is damaged, it will need to be replaced. This usually involves removing the front bumper and the old assembly, and then installing the new assembly.

Important Note: After replacing any components of the AGS system, you may need to reset the ECM using an OBD-II scanner. This will ensure that the ECM recognizes the new components and operates the AGS system correctly. The Nissan service manual is your best resource for specific procedures and torque specifications.

Benefits of a Properly Functioning AGS

Maintaining a properly functioning Active Grille Shutter system provides several benefits:

Improved Fuel Economy: By reducing aerodynamic drag and optimizing engine temperature, the AGS system can improve fuel economy by a measurable percentage, especially during highway driving.
Reduced Emissions: By allowing the engine to warm up faster, the AGS system can reduce emissions during the initial stages of driving.
Optimized Engine Temperature: The AGS system helps maintain the engine at its optimal operating temperature, which improves performance and reduces wear.

In conclusion, the 2017 Nissan Altima's Active Grille Shutter is a valuable system designed to improve fuel economy and reduce emissions. Understanding its components, operation, and troubleshooting procedures can help you keep your Altima running efficiently and reliably. By paying attention to this system and addressing any potential problems promptly, you can maximize its benefits and enjoy a smoother, more economical driving experience.