mypros+
Error code reference

Mitsubishi Air Conditioner Error Code Er3

Calibration error

Mitsubishi codesMitsubishi air conditioner codes

Calibration error - analog input bias and gain calibration values set too close.

First step from the service manual

Check settings of calibration parameters C3, C4, C6, and C7.

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

MyPros+ Max

Get the full diagnostic procedure for Er3.

  • Step-by-step tests with expected resistance, voltage, and continuity values
  • Wiring diagram references and connector pinouts from the OEM service manual
  • Verified part numbers when replacement is required
Get the full procedure

$29/month · Cancel anytime · Or $9.95 3-day pass

What Er3 means on a Mitsubishi air conditioner

Er3 on a Mitsubishi air conditioner indicates a calibration error in which the analog input bias and gain calibration values have been configured too close together. These calibration parameters define the scaling and offset of analog input signals, typically used to interpret sensor readings such as temperature or pressure into usable control values. When the bias (offset) and gain (scaling factor) values are set within too narrow a margin of each other, the controller cannot reliably distinguish or process the analog input signal, and the system flags the fault to prevent inaccurate operation.

The specific parameters involved are C3, C4, C6, and C7. These four calibration registers control the bias and gain for one or more analog input channels. If the values stored in these registers are incorrectly entered during commissioning, accidentally altered, or corrupted, the resulting proximity of bias and gain values triggers Er3. This is primarily a configuration and setup error rather than a hardware failure, meaning the cause is almost always found in the programmed parameter values rather than a failed physical component.

Diagnosing Er3 begins with accessing the unit's parameter settings and reviewing the current values stored in C3, C4, C6, and C7. The technician should compare these values against the correct calibration specifications for the installation. Any pair of bias and gain values that fall too close together must be corrected to restore a valid operating range. After correcting the parameters, the error should clear and normal operation should resume.

Source: manufacturer service documentation.

Common causes of Er3

  1. 01

    Incorrect calibration parameter entry during commissioning

    Wiring / connection

    When the unit is first installed and configured, calibration parameters C3, C4, C6, and C7 may be entered incorrectly, placing bias and gain values too close together. Reviewing the parameter settings against the correct values for the application will confirm this cause.

  2. 02

    Accidental parameter modification

    Wiring / connection

    A technician or user may have inadvertently changed one or more of the C3, C4, C6, or C7 values during a service visit or settings adjustment. Comparing current stored values to the original commissioning record will identify any unintended changes.

  3. 03

    Parameter corruption after power event

    Wiring / connection

    A power surge, sudden power loss, or voltage fluctuation can corrupt stored calibration values in the controller's memory, causing previously correct bias and gain values to become invalid or too similar. Inspecting parameters after any known power event is advisable.

  4. 04

    Default or reset values not suited to the installation

    Wiring / connection

    If the controller was reset to factory defaults or replaced, the default values for C3, C4, C6, and C7 may not match the calibration requirements of the specific analog inputs in the installation. The parameters must be reprogrammed to the correct application-specific values.

  5. 05

    Faulty control board retaining incorrect values

    Part replacement

    In rare cases, a failing control board may be unable to correctly store or read calibration parameters, causing repeated Er3 even after correct values are entered. This is suspected only after confirming the parameter values are correct and the error persists.

See the test procedure for each cause

Frequently asked questions about Er3

What does Er3 mean on a Mitsubishi air_conditioner?
Er3 indicates a calibration error in which the analog input bias and gain calibration values stored in parameters C3, C4, C6, and C7 are set too close together. This prevents the controller from accurately processing analog input signals. It is a configuration issue and not typically caused by a failed hardware component. Correcting the calibration parameter values will resolve the error.
How do I fix Er3 on a Mitsubishi air conditioner?
Access the unit's parameter settings and check the current values of calibration parameters C3, C4, C6, and C7. Compare these values to the correct calibration specifications for your installation and adjust any bias and gain values that are set too close together. After saving the corrected values, the error should clear. If the error persists after correction, inspect the control board for faults.
Will resetting my Mitsubishi air conditioner clear the Er3 error?
A simple power reset will not permanently clear Er3 because the fault is caused by stored calibration parameter values that remain in memory after a reset. The error will return unless the underlying parameter values in C3, C4, C6, and C7 are corrected. A full factory reset could change the stored values, but this would require reconfiguring all settings from scratch and may not produce the correct calibration values for your installation.
Is Er3 on a Mitsubishi air conditioner a safety concern?
Er3 itself is a calibration configuration error and does not directly indicate a dangerous condition. However, because the error means the controller cannot reliably interpret analog input signals, the unit may not operate correctly or may not respond accurately to temperature or pressure readings. It is advisable to address the error before continuing to run the system to avoid potential operational issues.
How much does it cost to repair an Er3 error on a Mitsubishi air conditioner?
If the error is caused by incorrect calibration parameter settings, the repair cost is primarily the labor charge for a qualified technician to access and correct the parameters, which typically falls in the range of 75 to 200 dollars depending on the technician and region. If a faulty control board is found to be the cause, parts and labor costs can range from 300 to 800 dollars or more. In most cases, Er3 is resolved through parameter adjustment alone without any parts replacement.

Related Mitsubishi air conditioner codes

All Mitsubishi air conditioner codes
View all 79 Mitsubishi air conditioner codes

78,000+ service manuals · 160,000+ error codes · 55+ brands

Get Started

$29/month · Cancel anytime · Or $9.95 3-day pass