How to Fix / Troubleshooting

Safety first: Turn OFF the breaker and wait several minutes before opening the outdoor unit.

Steps:

Access sensor: Remove the outdoor unit top or side panel (depending on model) to expose the condenser coil.
Locate thermistor: Find the small sensor clipped to the condenser coil or inserted into a coil pocket. It will have thin wires leading to the PCB.
Check connection: Ensure the thermistor connector is firmly attached to the outdoor PCB and not corroded.
Inspect cable: Look for cuts, chew marks, or UV damage on the sensor wires. Replace the sensor if the cable is damaged.
Re‑clip sensor: Make sure the sensor is properly attached to the coil surface as designed, for accurate temperature reading.
Test: Restore power and operate the unit. If E6 returns, the thermistor or PCB input is likely defective and should be replaced.

Note: Always use a Hitachi‑specified thermistor with the correct resistance curve for your model.

Unit stops, indoor unit shows E6, sometimes after running for a short time

Possible Causes