Coleman air conditioner shows E3 and may shut down on high pressure; outdoor fan may or may not be running.

Critical safety: High pressure can be dangerous. Turn OFF power at the breaker and outdoor disconnect. Do not attempt to open the refrigerant circuit unless you are EPA-certified.

• Check airflow around outdoor unit: Ensure at least 2–3 feet of clearance around the Coleman condenser. Remove leaves, grass, and debris from the coil and top grille.
• Clean the condenser coil: Remove the top grille (with power OFF). Use a soft brush to remove surface debris. Then apply a non-acidic coil cleaner and rinse gently from inside out with low-pressure water. Avoid bending fins.
• Inspect condenser fan operation: Restore power and briefly run the unit. Confirm the outdoor fan on the Coleman condenser starts promptly and spins at normal speed. If it hums, starts slowly, or stops intermittently, suspect a weak fan capacitor or failing fan motor.
• Check fan capacitor: With power OFF and capacitor discharged, remove the fan capacitor and test its microfarad rating with a meter. Replace if more than 10% out of spec.
• Look for airflow restrictions indoors: Dirty filters or blocked return grilles can also raise head pressure. Replace the air filter and ensure all supply/return vents are open.
• Refrigerant issues: If E3 persists after cleaning and verifying fan operation, the system may be overcharged or have a restriction. This requires a licensed HVAC technician with gauges to diagnose and correct.

Do not: Attempt to vent or add refrigerant yourself. This is illegal and hazardous.