Equinox 2005-2007, Torrent 2006-07

Powertrain Control Module

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Operation



The Powertrain Control Module (PCM) interacts with many emission related components and systems, and monitors 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 malfunction indicator lamp (MIL) operation and the DTC storage are dictated by the DTC type. A DTC is ranked as a Type A or Type B if the DTC is emissions related. Type C is a non-emissions related DTC.

The PCM is the control center of the engine controls system. The PCM controls the following components:



Fuel injection system
 
Ignition system
 
Emission control systems
 
On-board diagnostics
 
A/C and fan systems
 

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

Removal & Installation



  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.  
  3. Remove the powertrain control module (PCM) and PCM bracket from the battery box cover.
  4.  
  5. Remove the PCM bracket from the PCM.
  6.  
  7. Disconnect the PCM wire harness from the battery box cover.
  8.  
  9. Disconnect the negative battery cable.
  10.  
  11. Remove the PCM connectors from the PCM.
  12.  
  13. Remove the PCM from the vehicle.

    Click image to see an enlarged view

    Fig. Removing the PCM (1) and bracket (2) from battery box cover on 3.4L engine

  14.  

To install:

  1. Install the PCM to the vehicle.
  2.  
  3. Install the PCM connectors to the PCM.
  4.  
  5. Connect the negative battery cable.
  6.  
  7. Connect the PCM wire harness to the battery box cover.
  8.  
  9. Install the PCM bracket to the PCM.
  10.  
  11. Install the PCM bracket to the battery box cover.
  12.  
  13. Reprogram the PCM.
  14.  

 
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