E7

Indoor Unit Communication Receive Error

Mitsubishi Electric · PAR-21MAA MA Remote Controller

What does E7 mean?

The indoor unit has detected an error in receiving communication signals from the outdoor unit. This indicates a problem with the data transmission path from the outdoor unit or the indoor unit's receiving circuit, leading to a loss of control and coordination.

Repair Steps

  1. 1

    Verify the indoor/outdoor connecting wire terminations match the wiring diagram for correct connection.

  2. 2

    Inspect the indoor/outdoor connecting wire and power supply for signs of electrical noise interference that could disrupt signal reception.

  3. 3

    Cycle power to the unit (turn off, then on again) to re-check for the error.

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Verified technical data. Last updated: March 2026
Source: Mitsubishi Electric PAR-21MAA MA Remote Controller
Mitsubishi Electric Error E7: Indoor Unit Communication Receive Error — Troubleshooting Guide | ErrorLib