Easy one-page printout for the garage or repair shop
This summary uses the existing diagnostic information shown in full below.
This code means that a part of your car that helps control airflow to the engine is getting too hot.
The Active Grille Air Shutter is a system that opens and closes vents in the front of the car to manage airflow and improve fuel efficiency. If it overheats, it may not work properly.
The P2C78 code indicates that the Active Grille Air Shutter Module D has detected an over-temperature condition. This can lead to malfunctioning of the shutters, affecting engine cooling and aerodynamics.
• Check engine light is on
• Reduced fuel efficiency
• Engine overheating
• Faulty Active Grille Air Shutter Module
• Electrical short or open circuit in the module wiring
• Obstruction or debris causing overheating
Active Grille Air Shutter: A system that controls airflow to the engine to improve aerodynamics and fuel efficiency.
OBD-II: On-Board Diagnostics, a standardized system for vehicle self-diagnosis and reporting.
• Perform a visual inspection of the grille shutters for obstructions.
• Check the wiring and connectors for signs of damage or corrosion.
• Use a scan tool to verify the temperature readings from the module.
• Clear any obstructions from the grille shutters.
• Repair or replace damaged wiring or connectors.
• Replace the Active Grille Air Shutter Module if faulty.
• OBD-II scanner
• Multimeter
• Basic hand tools
$150 - $500
Moderate
• Ford F-150
• Chevrolet Silverado
• GMC Sierra
• Regularly inspect the grille for debris.
• Ensure proper maintenance of the vehicle's cooling system.
• Avoid driving through deep water which may damage the shutters.
Cooling System
• Avoid driving the vehicle until the issue is resolved to prevent engine damage.
• Consult with a certified mechanic for a thorough diagnosis.
Check with the vehicle manufacturer for warranty coverage on emission-related components.
This code has become more common with the introduction of active grille systems in modern vehicles to improve aerodynamics and fuel efficiency.
Moderate – It should be addressed soon to prevent potential engine overheating.
Ignoring this issue could lead to engine damage, which may not be covered under warranty if neglected.
• Engine running at normal operating temperature
• Vehicle stationary and in a safe location
Located at the front of the vehicle, integrated into the grille area.
Q: Can I drive with a P2C78 code?
A: It's not recommended as it could lead to engine overheating.
Q: How do I reset the P2C78 code?
A: After repairs, use an OBD-II scanner to clear the code.
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