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Error code reference

Mitsubishi Air Conditioner Error Code E.OPT

Option fault

Mitsubishi codesMitsubishi air conditioner codes

Option fault - various causes including incorrect power supply connection with FR-HC2/FR-CV, missing plug-in option for torque command, or communication option with password lock.

First step from the service manual

Check AC power supply connections, plug-in option connections, and Pr.296 password lock setting.

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

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What E.OPT means on a Mitsubishi air conditioner

The E.OPT error code on a Mitsubishi air conditioner indicates an option fault within the drive or control system. This fault is not tied to a single component failure but instead covers several distinct configuration and hardware issues related to optional plug-in modules and external converter connections. The error surfaces when the control board detects an inconsistency or conflict in how optional accessories are installed, powered, or configured.

One common trigger is an incorrect AC power supply connection associated with the FR-HC2 or FR-CV converter units. These are power factor correction or regenerative converter options, and if their AC input wiring is improperly connected or phased incorrectly relative to the main drive supply, the E.OPT fault will activate. A second trigger is the absence of a required plug-in option card when a torque command mode has been selected. If the drive is configured to receive torque commands through an option board and that board is not physically installed, the system faults immediately on startup.

The third cause involves a communication option card that has been secured with a password lock through parameter Pr.296. When a password lock is active and the system cannot authenticate or clear the lock condition, the option fault is triggered. Diagnostics should begin by verifying all AC supply connections to any connected converter units, confirming that the correct plug-in option board is seated properly in its slot, and checking the Pr.296 setting to determine whether a password lock is preventing normal option communication.

Source: manufacturer service documentation.

Common causes of E.OPT

  1. 01

    Incorrect AC power supply connection to FR-HC2 or FR-CV

    Wiring / connection

    If a regenerative converter or power factor correction unit such as the FR-HC2 or FR-CV is connected, incorrect AC input wiring relative to the main drive supply will trigger this fault. Check that the AC supply connections to these converter units are correctly phased and matched to the drive input.

  2. 02

    Missing plug-in option card for torque command

    Part replacement

    When the drive is configured for torque command operation, it expects a specific plug-in option board to be installed. If that board is absent or not fully seated in its slot, the E.OPT fault will appear at startup. Inspect the option card slots and confirm the required board is installed.

  3. 03

    Password lock active on communication option via Pr.296

    Wiring / connection

    The parameter Pr.296 controls password lock settings for communication option cards. If a password lock has been set and is preventing normal option operation, the drive will register an option fault. Review the Pr.296 setting and clear or enter the correct password to restore normal function.

  4. 04

    Plug-in option card not fully seated or damaged

    Wiring / connection

    Even when the correct option card is present, a loose connection or damaged card edge connector can cause the drive to report an option fault. Remove and reseat the option board, inspecting the connector pins for damage or corrosion.

  5. 05

    Incompatible or incorrect option card installed

    Part replacement

    Installing an option card that does not match the drive model or the configured operating mode can produce an E.OPT fault. Verify that the installed option card is the correct type for the drive and the selected control mode.

See the test procedure for each cause

Frequently asked questions about E.OPT

What does E.OPT mean on a Mitsubishi air_conditioner?
E.OPT indicates an option fault, meaning the drive has detected a problem with an installed or expected plug-in option card, an external converter connection, or a parameter configuration conflict. The fault covers three main scenarios: incorrect AC wiring to an FR-HC2 or FR-CV converter, a missing option card required for torque command mode, or a communication option card with an active Pr.296 password lock. A technician needs to identify which of these three conditions applies before attempting a repair.
How do I fix the E.OPT error on my Mitsubishi unit?
Start by checking all AC power supply connections to any connected converter units such as the FR-HC2 or FR-CV, making sure the wiring is correct and properly phased. Next, inspect the option card slots inside the drive to confirm the required plug-in board is present and fully seated. Finally, access the Pr.296 parameter to check whether a password lock is active on a communication option and clear it if necessary. If the fault persists after addressing these areas, the option card itself may need replacement.
Is it safe to continue running the unit with an E.OPT error?
The E.OPT fault will typically prevent the drive from operating normally, so continued operation is not possible until the fault is resolved. Attempting to force operation while an option card is missing or incorrectly configured could lead to improper motor control or system instability. Power down the unit and perform diagnostics before attempting to restart.
How much does it cost to repair an E.OPT fault on a Mitsubishi system?
If the issue is a wiring error or a password lock setting, the repair cost is primarily labor, typically ranging from $75 to $200 depending on the technician and location. If a plug-in option card needs to be purchased and installed, parts costs can add $100 to $400 or more depending on the specific card required. Getting an accurate quote requires identifying which of the three underlying causes applies to your system.
Will resetting the unit clear the E.OPT error code?
A simple power cycle or reset will not permanently clear the E.OPT fault if the underlying cause has not been corrected. The error will return as soon as the drive re-checks its option configuration on startup. You must resolve the root cause, whether that is fixing the wiring, installing the correct option card, or clearing the Pr.296 password lock, before the fault will stay cleared.

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