Thermostat shows E2 and will not control heating or cooling properly

Safety first: Turn off power to the HVAC system at the breaker before working on low-voltage wiring.

Steps to troubleshoot E2 remote sensor error:

• 1. Identify remote sensor: Confirm that a Goodman-compatible remote indoor sensor is actually installed and wired to the thermostat's sensor terminals (often labeled S1/S2 or RS1/RS2).
• 2. Inspect sensor wiring: Remove the thermostat from the wall and check that the sensor wires are firmly attached and not frayed or shorted together. Tighten any loose terminal screws.
• 3. Check sensor at remote location: Locate the remote sensor on the wall or return duct. Inspect for physical damage, paint over the sensor, or moisture intrusion. Ensure the sensor housing is intact.
• 4. Test resistance: With power off, disconnect the sensor wires at the thermostat and measure resistance across the two sensor leads with a multimeter. Compare to Goodman sensor specifications (typically a specific kΩ value at room temperature). Infinite or near-zero resistance indicates a failed sensor or shorted cable.
• 5. Bypass sensor: Temporarily remove the remote sensor wiring and configure the thermostat to use its internal sensor only (if supported). If E2 clears, the remote sensor or its wiring is defective.
• 6. Replace faulty component: Replace the remote sensor if resistance is out of range, or replace/repair the cable run if continuity is poor or shorted.