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Home >> Cadillac >> 2004 >> CTS Base, 3.6 7 >> Repair and Diagnosis >> Engine Performance >> System >> Engine Controls - 3.6L - Introduction >> Repair Instructions >> Engine Control Module (ECM) Replacement >> Removal Procedure
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Removal Procedure

NOTE: Always turn the ignition off when installing or removing the ECM connectors in order to prevent damage to the components.
    IMPORTANT: It is necessary to record the remaining engine oil life. If the replacement module is not programed with the remaining engine oil life, the engine oil life will default to 100%. If the replacement module is not programmed with the remaining engine oil life, the engine oil will need to be changed at 5000 km (3,000 mi) from the last engine oil change.
    IMPORTANT: It is necessary to record the remaining automatic transmission fluid life. If the replacement module is not programed with the remaining automatic transmission fluid life, the automatic transmission fluid life will default to 100%. If the replacement module is not programmed with the remaining automatic transmission fluid life, the automatic transmission fluid will need to be changed at 83000 km (50,000 mi) from the last automatic transmission fluid change.
  1. Using a scan tool, retrieve the percentage of remaining engine oil and the remaining automatic transmission fluid life. Record the remaining engine oil and the remaining automatic transmission fluid life.
  2. Turn the ignition OFF.
    3. IMPORTANT: Ensure that there is no main relay circuit voltage (ECM Fuse).
  3. Use a DVOM in order to measure the main relay circuit voltage at the ECM fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  4. Disconnect the battery negative cable. Refer to Battery Negative Cable Disconnect/Connect Procedure in Engine Electrical.
  5. Remove the ECM fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  6. Remove the TCM/IPC fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  7. Remove the ECM/TCM fuse in the underhood fuse block. Refer to Electrical Center Identification Views in Wiring Systems.
  8. Unlock the chassis side (upper) ECM electrical connector.
      Fig 1: Depressing ECM Electrical Connector Lever Lock
      GM1285259Courtesy of GENERAL MOTORS CORP.
    1. Depress the ECM electrical connector lever lock (1).
    2. Simultaneously rotate the ECM connector clamp lever and depress the lock slide (2).
    9. NOTE: In order to prevent any possible electrostatic discharge damage to the ECM, do not touch the connector pins.
    Fig 2: View Of Upper ECM Connector
    GM1343429Courtesy of GENERAL MOTORS CORP.
  9. Remove the body side (upper) ECM connector.
    10. Fig 3: View Of ECM Wiring Harness Connector
    GM945720Courtesy of GENERAL MOTORS CORP.
  10. Unlock and remove the engine side (lower) ECM connector.
    11. Fig 4: Removing ECM Redundant Ground Wire And Bolt From ECM
    GM1343434Courtesy of GENERAL MOTORS CORP.
  11. Remove the ECM redundant ground wire and bolt (2) from the ECM.
    12. Fig 5: Removing ECM Bolts
    GM887860Courtesy of GENERAL MOTORS CORP.
  12. Remove the ECM bolts.
  13. Remove the ECM.
  14. If you are replacing the ECM bracket, perform the following steps:
    15. Fig 6: View Of Engine Wiring Harness Bracket Bolt - Top Of ECM Bracket
    GM945521Courtesy of GENERAL MOTORS CORP.
  15. Remove the electrical connector bracket and bolt from the ECM bracket.
    16. Fig 7: Removing Ground Wire And Bolt From ECM Bracket
    GM945670Courtesy of GENERAL MOTORS CORP.
  16. Remove the ground wire and bolt from the ECM bracket.
    17. Fig 8: View Of Engine Wiring Harness Bracket Bolt - Side Of ECM Bracket
    GM945513Courtesy of GENERAL MOTORS CORP.
  17. Remove the wire harness retainer and bolt from the side of the ECM bracket.
    18. Fig 9: Removing ECM Bracket Bolts
    GM887861Courtesy of GENERAL MOTORS CORP.
  18. Remove the ECM bracket bolts (2 and 3).
  19. Remove the ECM bracket (1).
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