Display shows E2 and unit shuts down shortly after starting

Safety first: Turn off power and gas. Let the tank cool before touching any piping or sensors.

• Locate outlet sensor: The Giant outlet temperature sensor is usually mounted at or near the hot water outlet nipple or on the upper tank area under the access cover.
• Inspect and reseat: Disconnect the sensor plug from the control board, check for corrosion or moisture, dry if needed, and reconnect firmly.
• Check wiring: Trace the harness from the outlet sensor to the control board. Ensure it is not pinched behind the jacket or burned near the burner compartment.
• Measure resistance: With power off, measure the thermistor resistance and compare to Giant’s spec chart. Replace the outlet temperature sensor if readings are out of range.
• Control replacement: If a known‑good sensor still triggers E2, the Giant control board’s sensor circuit is likely defective and should be replaced by a professional.