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Error code reference

Mitsubishi Air Conditioner Error Code E.LCI

4 mA input fault

Mitsubishi codesMitsubishi air conditioner codes

4 mA input fault - analog input current is 2 mA or less for time set in Pr.778 (when Pr.573 = 2 or 3).

First step from the service manual

Check for a break in the wiring for the analog current input.

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

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What E.LCI means on a Mitsubishi air conditioner

The E.LCI error code on a Mitsubishi air conditioner indicates a 4 mA analog input fault. This fault is triggered when the analog current signal received at the designated input terminal drops to 2 mA or below and remains at that level for the duration specified by parameter Pr.778. This condition is only active when parameter Pr.573 is set to either 2 or 3, which configures the unit to accept a 4-20 mA analog current signal for external control functions such as frequency reference or process feedback. The 4-20 mA standard uses 4 mA as its baseline live-zero signal, so a reading at or below 2 mA indicates the signal has fallen well outside the valid operating range.

The most common cause of this fault is a break or open circuit in the wiring connected to the analog current input terminals. Because a true 4-20 mA loop requires a continuous path for current to flow, any disconnection, broken conductor, loose terminal, or corroded connector will cause the loop current to drop to zero or near zero, triggering the E.LCI fault. The Pr.778 timer parameter adds a delay before the fault is declared, which helps filter out momentary signal interruptions but means a genuine wiring failure will eventually latch the fault. Technicians should also consider a failed signal source, such as a transmitter or controller output card that has lost power or developed an internal fault, as these can also cause the current loop to collapse below the 2 mA threshold.

Source: manufacturer service documentation.

Common causes of E.LCI

  1. 01

    Broken or open wiring at the analog input

    Wiring / connection

    A broken conductor, disconnected terminal, or severed wire in the 4-20 mA current loop will cause loop current to drop to zero, immediately falling below the 2 mA fault threshold. Inspect all wiring between the signal source and the analog input terminals for continuity.

  2. 02

    Loose or corroded terminal connection

    Wiring / connection

    A loose screw terminal or corroded contact point at either the controller output or the air conditioner input terminal block can introduce enough resistance to interrupt the current loop. Check all terminal connections for tightness and signs of oxidation.

  3. 03

    Failed or unpowered signal source device

    Part replacement

    If the external transmitter, PLC analog output card, or controller providing the 4-20 mA signal has lost power or failed internally, the loop current will collapse. Verify the signal source device is powered and outputting a valid current in the 4-20 mA range.

  4. 04

    Incorrect parameter configuration

    Wiring / connection

    If Pr.573 was set to 2 or 3 without a corresponding 4-20 mA signal source actually connected and active, the input will read near zero and trigger E.LCI. Confirm that the parameter settings match the actual wiring configuration of the installation.

  5. 05

    Damaged analog input circuit on the control board

    Part replacement

    If wiring and the external signal source both check out correctly but the fault persists, the analog input circuitry on the control board may have been damaged by a wiring fault or voltage spike. This would require control board replacement.

See the test procedure for each cause

Frequently asked questions about E.LCI

What does E.LCI mean on a Mitsubishi air_conditioner?
E.LCI indicates a 4 mA analog input fault, meaning the current signal at the analog input terminal has dropped to 2 mA or below for the time period set in parameter Pr.778. This fault only activates when parameter Pr.573 is configured to 2 or 3, which sets the unit to expect a 4-20 mA external control signal. The error signals that the current loop has lost signal, most often due to a wiring break or a failed signal source device.
Can I fix E.LCI myself, or do I need a technician?
The first diagnostic step is checking the analog input wiring for breaks, loose terminals, or disconnected conductors, which is something a knowledgeable DIYer can perform. However, if the fault points to a failed signal source device, a misconfigured parameter such as Pr.573 or Pr.778, or a damaged control board, a qualified HVAC or controls technician should handle the repair. Working with control wiring and parameter programming requires familiarity with the specific system.
Is it safe to keep running my air conditioner with an E.LCI error?
The E.LCI fault indicates the unit is not receiving a valid external control signal, which means it cannot respond correctly to whatever process or frequency reference that signal was providing. Continuing to operate the unit in this condition could result in improper operation or loss of control. It is best to investigate and resolve the fault before returning the unit to normal service.
Will resetting the unit clear the E.LCI error?
A reset may temporarily clear the fault display, but E.LCI will return if the underlying cause has not been corrected. Because the fault latches after the analog input current remains at or below 2 mA for the duration set in Pr.778, the signal source or wiring issue must be resolved first. Repeated resets without fixing the root cause will not restore normal operation.
How much does it cost to repair an E.LCI error on a Mitsubishi air conditioner?
Repair costs vary significantly depending on the cause. If the fix involves repairing or reconnecting wiring, costs may be limited to a service call fee, typically in the range of $75 to $200. If the external signal source device such as a transmitter or PLC output card needs replacement, parts alone can range from $50 to several hundred dollars depending on the device. Control board replacement, if required, can bring total costs to $300 to $700 or more including labor.

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