e4
Moderate
York · HVAC Systems (AC, Furnaces, Heat Pumps & Thermostats)
Discharge Temperature Sensor Fault
Quick Answer
Error code E4 on your York HVAC Systems (AC, Furnaces, Heat Pumps & Thermostats) means: Discharge Temperature Sensor Fault. This is usually fixable — see the step-by-step guide below.
Likely Causes
How to Fix It
1
Locate the discharge line thermistor on the compressor discharge pipe
2
Measure the thermistor resistance and compare to the manufacturer's temperature-resistance chart
3
Check the connector at the outdoor control board for corrosion or loose pins
4
Inspect the sensor wire for physical damage along its routing
5
Replace the thermistor if resistance is out of specification
Pro Tip
This fix requires some technical knowledge. If you're unsure about any step, consider contacting support or a qualified technician.
Parts You May Need
Discharge line thermistor
Insulation tape
Wire connectors
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