Mitsubishi Error Code 5: Outdoor Thermistor Open/Short

Severity
Warning
Type
led blink count
Where to look
indoor unit led
Estimated repair cost: $100 — $250 (parts + labor)
Warning: Your Mitsubishi HVAC system has detected an issue with the outdoor thermistor and has shut down to prevent damage.

LED Blink Pattern

How to Fix Mitsubishi Code 5

  1. Check for any visible damage to the outdoor unit and the wiring
  2. If the issue persists, contact a professional HVAC technician for a thorough diagnosis and repair

How to Reset Mitsubishi Code 5

  1. Turn off the unit using the remote control or wall controller.
  2. Turn off the circuit breaker for the outdoor and indoor units. Wait 60 seconds.
  3. Restore power at the breaker.
  4. Turn the unit on with the remote control. If the error returns, the fault needs professional diagnosis.

Resetting clears the code from the display but does not fix the underlying fault. If the code returns after reset, proceed to the diagnostic steps above.

What Does Mitsubishi Error Code 5 Mean?

The Mitsubishi 5 error, also known as an 'Outdoor Thermistor Open/Short', indicates that your system has detected an issue with the outdoor thermistor. This component is responsible for measuring the temperature outside your home and communicating this information to your HVAC system. If the system detects that the thermistor is not functioning properly, it will shut down to prevent further damage. This error is typically caused by a faulty thermistor, but it could also be due to a problem with the wiring or the control board.

Common Causes

  • Faulty outdoor thermistor
  • Damaged wiring to the thermistor
  • Issues with the control board

Diagnostic Steps

If... Check Expected
The outdoor unit is not running Measure the resistance of the thermistor using a multimeter Resistance should be within the manufacturer's specified range for the current temperature
The thermistor resistance is out of range Inspect the wiring to the thermistor for any damage or breaks Wiring should be intact and free of damage

Applicable Mitsubishi Models

Replacement Parts

Part OEM Number Est. Cost Where to Buy
Outdoor Thermistor 530-243-001

Related Codes on Same Models

Other codes that affect the same Mitsubishi model families as 5.

Code Description Severity
1 Indoor/Outdoor Mismatch Warning
2 Power Supply Phase Error Warning
3 Communication Error Warning
4 Inverter Error Warning
6 Indoor Freeze/Overheat Warning
7 Outdoor Freeze/Overheat Warning
E6 Indoor/Outdoor Communication Error Warning
E9 Indoor/Outdoor Communication Fault Warning
P1 Intake Sensor Error Warning
P2 Indoor Pipe Thermistor Error Warning