2021 Mazda 3 BaseFACTORY OEM SERVICE PROCEDURE

Pcm Removal/Installation

CAUTION:
  • There are two types of PCM settings. If the incorrect PCM is installed, it could cause interference with engine control.
  • When replacing the PCM, verify the first four digits of the part number indicated on the PCM label before replacement, and replace the PCM with one having the same part number.
    G13175492Courtesy of MAZDA MOTORS CORP.
  • When replacing the PCM, perform the configuration to assure that the system operates correctly. (See CONFIGURATION .)
  1. When replacing the PCM, perform the configuration using the following procedure.
    1. Connect the M-MDS to the DLC-2.
    2. Switch the ignition ON (engine off).
    3. Activate the MMDS and perform the following procedure.
      1. Press [Start] to start the vehicle identification.
      2. Press the [Toolbox] tab.
      3. Press the [Work Support] icon.
      4. Press [Configuration].
      5. Press [Run] to perform the configuration.
      6. Press [PCM].
      7. Verify that the ignition is switched ON (engine off) and press [Next].
        • If the ignition cannot be switched ON (engine off), leave it as it is and press [Next].
      8. When [Install the new ECU] is displayed, move to the PCM replacement procedure.
  2. Disconnect the negative battery terminal. (See NEGATIVE BATTERY TERMINAL DISCONNECTION/CONNECTION (US) .)
  3. Remove the PCM together with the battery tray as a single unit. (See BATTERY REMOVAL/INSTALLATION .)
  4. Remove in the order indicated in the table.
  5. Install in the reverse order of removal.
  6. If the PCM is replaced, perform the following procedure.
NOTE:
  • Depending on the vehicle conditions, the configuration after PCM replacement may use the data read from the PCM before replacement or the data as of shipment from manufacturer (As-Built data).
  • The data used for the configuration is displayed on the lower part of the M-MDS display when the configuration is completed.
  1. Continue to perform configuration following the instructions on the M-MDS screen.
  2. Perform the immobilizer system-related part programming using the M-MDS. (See IMMOBILIZER SYSTEM-RELATED PARTS PROGRAMMING (US) .)
  3. If the configuration is performed using the As-Built data, write the coupling component characteristic value. (AWD) (See COUPLING COMPONENT CALIBRATION DATA WRITING .)
  4. Perform the DTC inspection. (See DTC INSPECTION .)
  • If the DTC is displayed again, repair the malfunctioning location according to the applicable DTC troubleshooting.
Fig 1: PCM Components With Torque Specification
G13714333Courtesy of MAZDA MOTORS CORP.
PART DESCRIPTION

1 PCM
2 PCM bracket
Factory Service Tools

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When to See a Mechanic

Stop DIY work and contact a certified mechanic immediately if any of the following apply:

  • • You smell fuel, burning insulation, or see smoke.
  • • Brakes feel soft, pull hard to one side, or make grinding noises.
  • • The engine overheats, stalls repeatedly, or misfires under load.
  • • You are missing required tools, torque specs, or safe lifting equipment.
  • • You are not confident in the next step or safety outcome.

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