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Error code reference

Mitsubishi Air Conditioner Error Code LOCd

Password locked

Mitsubishi codesMitsubishi air conditioner codes

Password locked - password function is active, display and setting of parameters are restricted.

First step from the service manual

Enter the password in Pr.297 to unlock the password function.

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

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What LOCd means on a Mitsubishi air conditioner

The LOCd code on a Mitsubishi air conditioner indicates that the password protection function is currently active. This is not a fault or failure code in the traditional sense. Instead, it is a security feature built into the unit's parameter control system that restricts access to display and adjustment of operating parameters. When password protection is enabled, the controller prevents unauthorized changes to system settings, effectively locking out configuration access until the correct credentials are entered.

The password lock function is controlled through parameter Pr.297 in the unit's parameter menu. When this parameter has been configured with a password, the LOCd indicator appears to signal that the interface is operating in a restricted mode. Technicians or installers commonly enable this feature to prevent end users from accidentally altering critical system settings such as operating limits, timer configurations, or performance parameters. The restriction applies to both the display and the setting of parameters, meaning that sensitive values may also be hidden from view until the lock is cleared.

This condition is entirely software-driven and does not indicate any hardware fault, refrigerant issue, or electrical failure within the system. The unit itself continues to operate normally in its currently configured state while LOCd is displayed. Resolution requires entering the correct password through Pr.297. If the password has been lost or forgotten, escalation to a qualified HVAC technician is recommended, as recovery procedures may require access to installer-level menus or coordination with Mitsubishi technical support.

Source: manufacturer service documentation.

Common causes of LOCd

  1. 01

    Installer or technician enabled password protection

    Wiring / connection

    The most common reason for LOCd is that the installing technician or HVAC contractor deliberately activated the password function through parameter Pr.297 to prevent end users from changing critical system settings. Check with the installer for the password.

  2. 02

    Previous service personnel set an unknown password

    Wiring / connection

    If the unit has been serviced by multiple technicians over time, a previous service visit may have resulted in a password being set that current users or technicians are unaware of. Review any available service records or contact prior service providers.

  3. 03

    Accidental password activation during parameter navigation

    Wiring / connection

    In some cases, users navigating the parameter menu may inadvertently enable the password function by entering a value in Pr.297. If the password was set accidentally, the value entered at that time would be required to unlock the system.

  4. 04

    Password set as part of a commissioning procedure

    Wiring / connection

    During initial commissioning of the unit, some installation procedures include enabling the password lock as a final step to secure the configuration. Documentation from the commissioning process should contain the password used.

See the test procedure for each cause

Frequently asked questions about LOCd

What does LOCd mean on a Mitsubishi air_conditioner?
LOCd indicates that the password protection function is active on your Mitsubishi air conditioner. This feature restricts access to the display and adjustment of system parameters. The unit continues to operate normally under its existing settings, but configuration changes cannot be made until the correct password is entered through parameter Pr.297. This is a security feature, not a malfunction.
How do I fix the LOCd code on my Mitsubishi air conditioner?
To clear the LOCd code, navigate to parameter Pr.297 in the unit's parameter menu and enter the correct password. Once the valid password is accepted, the password lock will be deactivated and full access to parameters will be restored. If you do not know the password, contact the technician or contractor who installed or last serviced the unit, as they are most likely to have set and recorded it.
Is the LOCd code on my Mitsubishi air conditioner a safety concern?
No, LOCd does not indicate any safety issue, mechanical failure, or electrical fault. The air conditioner continues to operate normally while this code is displayed. The code simply means that parameter access is restricted due to an active password lock. There is no need for immediate service based on this code alone.
Will resetting my Mitsubishi air conditioner clear the LOCd code?
A standard power reset will not clear the LOCd code because the password lock is stored as a parameter setting within the unit's memory. Cycling power does not reset parameter configurations. The only way to remove the LOCd indicator is to enter the correct password through parameter Pr.297 or, in cases of a lost password, to work with a qualified technician who can access installer-level recovery options.
How much does it cost to resolve the LOCd code on a Mitsubishi air conditioner?
If you have access to the password, resolving LOCd costs nothing since it only requires entering the code in parameter Pr.297. If a technician is needed to recover or reset a lost password, you can expect to pay a service call fee, typically in the range of $75 to $200 depending on your location and the contractor's rates. No parts are required to resolve this condition.

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