CTS 2006-2007, CTS-V 2005-2007, DTS 2006-2007

Electronic Control Module

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Operation



The Engine Control Module (ECM) interacts with many emission related components and systems, and monitors the emission related components and systems for deterioration. OBD II diagnostics monitor the system performance and a Diagnostic Trouble Code (DTC) sets if the system performance degrades.

The ECM constantly monitors the information from various sensors and other inputs, and controls the systems that affect the vehicle performance and the emissions. The ECM also performs diagnostic tests on various parts of the system. The ECM can recognize operational problems and alert the driver via the MIL. When the ECM detects a malfunction, the ECM stores a DTC. The condition area is identified by the particular DTC that is set. This aids the technician in making repairs.

The ECM is in the engine compartment. The ECM is the control center of the engine controls system. The ECM controls the following components:



The fuel injection system
 
The ignition system
 
The emission control systems
 
The on-board diagnostics
 
The A/C and fan systems
 
The Throttle Actuation Control (TAC) system
 

The ECM constantly monitors the information from various sensors and other inputs, and controls the systems that affect the vehicle performance and the emissions. The ECM also performs diagnostic tests on various parts of the system. The ECM can recognize operational problems and alert the driver via the MIL. When the ECM detects a malfunction, the ECM stores a DTC. The condition area is identified by the particular DTC that is set. This aids the technician in making repairs.

Removal & Installation



2.8L & 3.6L Engines
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Turn the ignition OFF.
  4.  
  5. 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.
    WARNING
    Ensure that there is no main relay circuit voltage ECM Fuse.

  6.  
  7. Use a DVOM in order to measure the main relay circuit voltage at the ECM fuse in the underhood fuse block.
  8.  
  9. Disconnect the battery negative cable.
  10.  
  11. Remove the ECM fuse in the underhood fuse block.
  12.  
  13. Remove the TCM/IPC fuse in the underhood fuse block.
  14.  
  15. Remove the ECM/TCM fuse in the underhood fuse block.
  16.  
  17. Unlock the chassis side (upper) ECM electrical connector.
  18.  
  19. Depress the ECM electrical connector lever lock.
  20.  
  21. Simultaneously rotate the ECM connector clamp lever and depress the lock slide.
    NOTE
    In order to prevent any possible electrostatic discharge damage to the ECM, do not touch the connector pins.

  22.  
  23. Remove the body side (upper) ECM connector.
  24.  
  25. Unlock and remove the engine side (lower) ECM connector.
  26.  
  27. Remove the ECM redundant ground wire bolt and wire from the ECM.
  28.  
  29. Remove the ECM bolts.
  30.  
  31. Remove the ECM.

    Click image to see an enlarged view

    Fig. Electronic Control Module (ECM) removal

  32.  

To install:

  1. Install the ECM.
  2.  
  3. Install the ECM bolts and tighten to 89 inch lbs. (10 Nm).
  4.  
  5. Install the ECM redundant ground and bolt to the ECM. Tighten the bolt to 44 inch lbs. (5 Nm).
  6.  
  7. Install the engine side (lower) ECM connector.
  8.  
  9. Install the body side (upper) ECM connector.
  10.  
  11. Install the ECM/TCM fuse in the underhood fuse block.
  12.  
  13. Install the TCM/IPC fuse in the underhood fuse block.
  14.  
  15. Install the ECM fuse in the underhood fuse block.
  16.  
  17. Connect the battery negative cable to the battery.
  18.  
  19. Program the ECM. For step-by-step programming instructions, please refer to the Techline Information System (TIS) terminal.
  20.  
  21. Turn OFF the ignition for at least 5 seconds after the programming event is complete.
  22.  

4.6L Engine
  1. Before servicing the vehicle, refer to the Precautions Section.
  2.  
  3. Using a scan tool, retrieve the percentage of remaining engine oil and automatic transaxle fluid life. Record the remaining engine oil and transaxle fluid life.
  4.  
  5. Ensure that the ignition is in the OFF position.
  6.  
  7. Disconnect the negative battery cable.
  8.  
  9. Disconnect the engine harness electrical connector from the Mass Air Flow/Intake Air Temperature (MAF/IAT) sensor.
  10.  
  11. Disconnect the Positive Crankcase Ventilation (PCV) fresh air tube quick connect fitting from the air duct.
  12.  
  13. Disconnect the secondary Air Injection (AIR) pump inlet tube quick connect fitting from the air cleaner upper housing.
  14.  
  15. Loosen the air cleaner outlet duct clamp at the throttle body.
  16.  
  17. Remove the air cleaner outlet duct from the throttle body.
  18.  
  19. Disengage the lower housing clips.
  20.  
  21. Disengage the upper housing front tabs from the lower housing.
  22.  
  23. Remove the air cleaner upper housing.
  24.  
  25. Disengage the engine harness electrical connector lever locks at the ECM.
  26.  
  27. Remove the engine harness electrical connectors from the ECM.
  28.  
  29. Remove the ECM from the air cleaner lower housing.

    Click image to see an enlarged view

    Fig. Engine Control Module (ECM) removal shown

  30.  

To install:

  1. Install the ECM to the lower air cleaner housing.
  2.  
  3. Install the engine harness electrical connectors to the ECM.
  4.  
  5. Engage the engine harness electrical connector lever locks at the ECM.
  6.  
  7. Install the air cleaner upper housing.
  8.  
  9. Engage the upper housing front tabs to the lower housing.
  10.  
  11. Engage the lower housing clips.
  12.  
  13. Install the air cleaner outlet duct to the throttle body.
  14.  
  15. Tighten the air cleaner outlet duct clamp at the throttle body. Tighten the clamp to 27 inch lbs. (3 Nm).
  16.  
  17. Connect the AIR pump inlet tube quick connect fitting to the air cleaner upper housing.
  18.  
  19. Connect the PCV fresh air tube quick connect fitting to the air duct.
  20.  
  21. Connect the engine harness electrical connector to the MAF/IAT sensor.
  22.  
  23. Connect the negative battery cable.
  24.  
  25. Program the ECM.
  26.  
  27. For step-by-step programming instructions, please refer to the Techline Information System (TIS) terminal.
  28.  
  29. Turn OFF the ignition for at least 5 seconds after the programming event is complete.
  30.  

Testing



  1. Use a scanner and try to communicate with the vehicles ECM.
  2.  
  3. Test all voltages and ground inputs to the ECM for an open circuit or high resistance.
  4.  
  5. Ensure that all ECM connections are clean and secure.
  6.  
  7. Check for any Technical Service Bulletins (TSB) associated with ECM problems.

    Click image to see an enlarged view

    Fig. Electronic Control Module (ECM)-C1 2.8L & 3.6L engines



    Click image to see an enlarged view

    Fig. Electronic Control Module (ECM)-C2 2.8L & 3.6L engines



    Click image to see an enlarged view

    Fig. Electronic Control Module (ECM)-C1 4.6L engine



    Click image to see an enlarged view

    Fig. Electronic Control Module (ECM)-C2 4.6L engine



    Click image to see an enlarged view

    Fig. Electronic Control Module (ECM)-C3 4.6L engine

  8.  

 
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