P2C73 — Active Grille Air Shutter C Stuck On

Causes

• Mechanically jammed shutter (ice, debris, bent linkage)
• Failed shutter actuator/motor (stalled or burnt windings)
• Faulty position/feedback sensor in the shutter assembly
• Open/short or high resistance in power, ground, or signal wiring/connectors
• Blown fuse or faulty relay supplying the actuator
• Loss of CAN/communication or controller fault

Symptoms

• Malfunction Indicator Lamp (MIL) or warning light illuminated
• Active grille shutter stuck open or closed (reduced airflow control)
• Possible reduced fuel economy or increased engine warm-up time
• Audible motor noise or grinding when actuator commanded
• Diagnostic trouble code P2C73 stored in PCM or module

What to check

• Read and record freeze frame and live data with a capable scan tool
• Visually inspect shutter C for ice, debris, broken fins, or binding linkage
• Inspect connectors and wiring for corrosion, damage, or loose pins at the actuator and PCM
• Check relevant fuses and relays for continuity and correct rating
• Use a scan tool to command the shutter and observe movement and feedback values
• Back-probe actuator power and ground while commanding to verify supply and ground integrity

Signal parameters

• Actuator supply voltage (key on/run): ~12–14.5 V expected (should be near battery voltage when commanded)
• Ground continuity: near 0 ohms to chassis ground when measured at connector
• Position/feedback sensor voltage: commonly 0.5–4.5 V range corresponding to closed↔open; should change smoothly when commanded
• Command signal (if PWM): duty cycle 0–100% corresponding to open/close commands from the controller
• Actuator current draw: typically small (hundreds of mA); sustained high current or spike indicates stall/short (>1–3 A depending on design)
• CAN or serial messages: shutter status/position messages should be present and updating in scan tool live data (frequency varies by vehicle)

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