Mitsubishi Air Conditioner Error E4
⚡ Quick Answer: The Mitsubishi Air Conditioner E4 error indicates a communication failure between the indoor and outdoor units. This may manifest as the E4 error code... ✅ DIY Fixable
What Does Error E4 Mean?
The Mitsubishi Air Conditioner E4 error indicates a communication failure between the indoor and outdoor units. This may manifest as the E4 error code appearing on the display, with the air conditioner becoming unresponsive or intermittently responding to remote commands. The issue is often related to remote controller signal errors, loose wiring, or faulty remote hardware.
Common Symptoms:
- Error E4 displayed on indoor unit or remote display
- Air conditioner unresponsive or intermittently responsive to remote commands
- Remote control operations ineffective
Possible Causes
- Remote controller communication or signal receiving error between remote and indoor unit (high)
- Disconnected, loose or incorrectly wired remote control signal line (medium)
- Faulty remote controller hardware (medium)
How to Fix Error E4
DIY Fix Basic Remote Communication Checks
- Turn off and restart the air conditioner to attempt clearing transient communication faults
- Check that the remote control has batteries installed correctly and functioning
- Ensure nothing is obstructing the line of sight if using IR communication
- Observe whether the remote operations reliably result in unit responses
Technician Only Inspect and Repair Remote Wiring and Communication
- Shut off power to the air conditioner and inspect remote transmission wiring at both indoor unit and remote terminals
- Verify wiring meets manufacturer specification (two-core cable, correct gauge, no shielding unless specified) and that terminations are secure
- Test the remote controller hardware and replace if necessary
- Check indoor unit signal receiving circuitry and replace control board components if defective
Parts needed: Remote controller unit, Remote signal cable, Indoor unit control board/receiver
- If the error persists after basic remote checks and cable inspection
- If there is any sign of damaged internal wiring or control board components
- If you are unsure about safely accessing internal unit wiring
Technical Specifications
| wattage | N/A |
|---|---|
| component | Control Board |
| resistance | N/A |
| part_number | Mitsubishi 938D100A20 |
| voltage_rating | 230V AC |
Common Questions
What does E4 error mean on Mitsubishi Air Conditioner?
E4 error indicates a communication failure between indoor and outdoor units, often making the air conditioner unresponsive.
Can I fix Mitsubishi Air Conditioner E4 error myself?
Yes, you can check the remote batteries, restart the unit, and ensure there are no obstructions.
How much does it cost to fix E4 error?
Repair costs typically range from $80 to $350, depending on parts and diagnostic time.
When should I call a technician for E4?
Call a technician if the error persists after basic checks or if there's visible damage to internal components.
Sources & References
- Mitsubishi Electric AC Fault Code E4 Explained (community)
Data last verified: 2026-07-01
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