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Error code reference

Mitsubishi Air Conditioner Error Code E.GF

Output side earth (ground) fault overcurrent

Mitsubishi codesMitsubishi air conditioner codes

Output side earth (ground) fault overcurrent - earth fault overcurrent detected on inverter output side.

First step from the service manual

Check for an earth (ground) fault in the motor and connection cable.

The complete diagnostic procedure includes additional test steps, resistance specifications, wiring diagram references, and component test points.

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What E.GF means on a Mitsubishi air conditioner

The E.GF error code on a Mitsubishi air conditioner indicates that an earth fault overcurrent condition has been detected on the output side of the inverter. The inverter output side refers to the electrical path between the inverter drive board and the compressor motor windings. When current leaks from one of these output phases to ground at a level that exceeds the inverter's protection threshold, the system immediately shuts down to prevent damage to the inverter module, compressor, and connected wiring. This is a protective shutdown, not a soft warning.

The most common origin of this fault is insulation breakdown within the compressor motor itself. Over time, thermal cycling, moisture ingress, and mechanical stress can degrade the winding insulation, allowing current to leak to the compressor casing or refrigerant circuit. The connection cable between the inverter board and the compressor is equally suspect, as chafed, pinched, or corroded conductors can create a leakage path to the chassis or refrigerant piping.

Diagnosis should begin with an insulation resistance test using a megohmmeter on the compressor motor windings and the associated wiring harness, with all connections to the inverter board disconnected first. A healthy motor typically shows insulation resistance well above 1 megohm. Readings close to zero or measurably low indicate a definitive fault location. If the wiring tests clean, the compressor motor itself should be considered the primary suspect and will likely require replacement.

Source: manufacturer service documentation.

Common causes of E.GF

  1. 01

    Failed compressor motor insulation

    Part replacement

    Degraded winding insulation inside the compressor allows current to leak to the compressor casing or ground. This is identified by a very low insulation resistance reading when testing the motor windings with a megohmmeter.

  2. 02

    Damaged compressor connection cable

    Part replacement

    The wiring harness running between the inverter board and the compressor can become chafed, pinched, or corroded, creating a direct path to ground. Visually inspect the cable for insulation damage and test each conductor for ground leakage.

  3. 03

    Moisture ingress into wiring or terminals

    Wiring / connection

    Water or condensation entering the compressor terminal block or connection points can create a low-resistance path to ground. Check for corrosion, water staining, or physical moisture at the compressor terminals and wiring connectors.

  4. 04

    Faulty inverter output stage

    Part replacement

    In some cases the inverter board itself develops an internal fault that incorrectly triggers the earth fault protection circuit. This is diagnosed only after the motor and wiring have been confirmed to be in good condition.

See the test procedure for each cause

Frequently asked questions about E.GF

What does E.GF mean on a Mitsubishi air_conditioner?
E.GF indicates that the inverter has detected an earth fault overcurrent condition on its output side, which is the electrical path between the inverter drive and the compressor motor. The unit shuts down immediately as a protective measure to prevent damage to the inverter, compressor, and wiring. The fault points to current leaking to ground somewhere in the compressor motor windings or the cable connecting the motor to the inverter. A technician will need to perform insulation resistance testing to pinpoint the source.
Can I fix an E.GF error myself?
This fault involves high-voltage inverter circuitry and compressor motor testing that requires specialized tools such as a megohmmeter and a thorough understanding of AC electrical safety. Most homeowners should not attempt this repair. A qualified HVAC technician is needed to safely test the motor insulation, inspect the connection cable, and determine whether the compressor or inverter board requires replacement.
Is it safe to run my Mitsubishi air conditioner with an E.GF error?
No, you should not attempt to operate the unit while this error is active. The E.GF code signals an active ground fault condition, which poses a risk of electrical shock, further damage to the inverter module, and potential fire hazard. The unit shuts itself down specifically because continuing to run under this condition is unsafe. Leave the system off until it has been properly diagnosed and repaired.
Will resetting the unit clear the E.GF error?
A power reset may temporarily clear the error display, but the fault itself will return as soon as the unit attempts to run the compressor again. Because E.GF is caused by a physical electrical fault in the motor or wiring, resetting the unit does not address the underlying problem. Repeated reset attempts without repairing the fault can cause additional damage to the inverter output stage.
How much does it cost to repair an E.GF error on a Mitsubishi air conditioner?
Repair costs vary significantly depending on the root cause. If only the connection cable requires replacement, costs are generally in the range of a few hundred dollars including labor. If the compressor motor has failed due to insulation breakdown, replacement costs can range from several hundred to over a thousand dollars depending on the unit size and parts availability. An inverter board replacement falls in a similar range. A proper diagnosis is essential before committing to any parts expenditure.

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