2004 Acura MDX BaseFACTORY OEM SERVICE PROCEDURE

PCM Replacement

  1. Connect the HDS to the data link connector (DLC) (A) located under the driver's side of the dashboard.
    Fig 1: Connecting HDS To DLC
    G03639841Courtesy of AMERICAN HONDA MOTOR CO., INC.
  2. Make sure the HDS communicates with the PCM. If it doesn't, skip steps 3 to  5 and clean the throttle body (see THROTTLE BODY CLEANING ) after this procedure.
  3. Turn the ignition switch ON (II).
  4. Select the INSPECTION MENU with the HDS.
  5. Do the TP POSITION CHECK in the ETCS TEST.
  6. Turn the ignition switch OFF.
  7. Jump the SCS line with the HDS.
  8. Remove the cover (A).
    Fig 2: Removing Cover
    G03639842Courtesy of AMERICAN HONDA MOTOR CO., INC.
  9. Disconnect the PCM connectors (B).
  10. Remove the bolts (C), then remove the PCM (D).
  11. Install a known-good PCM in the reverse order of removal.
  12. Open the SCS with the HDS.
  13. Turn the ignition switch ON (II).
    NOTE: For 2005-2006 models: DTC P0630 "VIN Not Programmed or Mismatch" may be stored because the VIN has not been programmed into the PCM; ignore it, and continue this procedure.
  14. Input the VIN to the PCM with the HDS.
  15. Rewrite the immobilizer code with the PCM replacement procedure in the HDS; it allows you to start the engine.
  16. Reset the PCM with the HDS.
  17. Do the PCM idle learn procedure (see PCM IDLE LEARN PROCEDURE ).
  18. Do the CKP pattern learn procedure (see CKP PATTERN CLEAR/CKP PATTERN LEARN ).
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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