Mitsubishi Electric All Systems

Mitsubishi Electric Error Code P4

Troubleshooting guide for the Mitsubishi Electric system fault P4.

What It Means

Abnormality or sensing failure detected in the indoor condensate drain sensor.

Possible Causes

  • Indoor condensate drain sensor abnormality.
  • Drain sensor circuit or connector fault.

Not sure which one it is — or if it's none of these? Try ACLogics today.

Disclaimer: This information is for general reference. Error codes can vary by model and production year. Always refer to your machine's specific manual and the information printed on the unit itself.
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Full Diagnosis

Abnormality of drain sensor

All Recorded Causes

Verify Before Replacing Parts

  1. Confirm the exact Mitsubishi Electric model family and default context before acting on a generic code description.
  2. Verify the sensor or thermistor reading against the expected range for the current operating condition, keeping in mind that the most likely cause listed above.
  3. Check the sensor harness and board connection before condemning the sensor itself; on Mitsubishi Electric units this is also where you'd confirm the next candidate on the list.
  4. After the correction, run the system long enough to confirm the default fault does not return under normal load.

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