Coleman air conditioner displays E2 and may run briefly then shut down; cooling performance is erratic.

Safety: Turn OFF power at the breaker and outdoor disconnect before opening any panels.

• Access the indoor coil: Remove the blower/coil access panel on the Coleman air handler or packaged unit.
• Locate the coil sensor: The sensor (thermistor) is usually clipped or strapped to the evaporator coil tubing near the middle of the coil.
• Check mounting: Ensure the sensor is firmly attached to the coil surface. If it has fallen off or is hanging, reattach using the original clip or a new metal clip/thermal tape so it makes good contact.
• Inspect wiring: Follow the sensor wires back to the control board. Look for cuts, pinched sections, or loose connectors. Reseat the plug on the Coleman control board.
• Test the sensor: With power OFF, disconnect the sensor and measure resistance. Compare to the temperature/resistance chart in the Coleman service manual. Replace the sensor if readings are open, shorted, or out of range.
• Evaluate the control board: If the sensor and wiring are good, the board’s sensor input may be defective. Replacement of the Coleman control board may be necessary.
• Restore operation: Reassemble, restore power, clear the code by cycling power, and verify the unit runs without E2 reappearing.

Note: Do not bend or damage the coil fins while working around the sensor.