Envoy, Rainer, Trailblazer 2006-2007

Powertrain Control Module

Print

Operation



4.2L Engine

The powertrain control module (PCM) constantly looks at the information from various sensors and other inputs and controls systems that affect vehicle performance and 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 malfunction indicator lamp (MIL). When the PCM detects a malfunction, the PCM stores a diagnostic trouble code (DTC). The problem area is identified by the particular DTC that is set. The control module supplies a buffered voltage to various sensors and switches. The input and output devices in the PCM include analog-to-digital converters, signal buffers, counters, and output drivers. The output drivers are electronic switches that complete a ground or voltage circuit when turned on. Most PCM controlled components are operated via output drivers. The PCM monitors these driver circuits for proper operation and, in most cases, can set a DTC corresponding to the controlled device if a problem is detected.

5.3L & 6.0L Engines

Refer to Engine Control Module (ECM).

Removal & Installation



4.2L Engine

NOTE
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.

  1. Using a scan tool, retrieve the percentage of remaining engine oil. Record the remaining engine oil life.
  2.  
  3. Disconnect the negative battery cable.
    WARNING
    In order to prevent internal damage to the PCM, the ignition must be OFF when disconnecting or reconnecting the PCM connector.



    Click image to see an enlarged view

    Fig. Disconnect the instrument panel wiring harness electrical connector (1) from the PCM-2006-2007 4.2L engine

  4.  
  5. Disconnect the instrument panel wiring harness electrical connector (1) from the PCM.
  6.  
  7. Disconnect the engine wiring harness electrical connectors (1) from the PCM.
    WARNING
    Do not touch the connector pins or soldered components on the circuit board in order to prevent possible ElectroStatic Discharge (ESD) damage to the PCM.

  8.  
  9. Disengage the top 2 retainers and remove the PCM from the bracket.

    Click image to see an enlarged view

    Fig. Disengage the top retainers and remove the PCM from the bracket-2006-2007 4.2L engine



    Click image to see an enlarged view

    Fig. Removal of the PCM and bracket, bolts and nuts-2006-2007 4.2L engine

  10.  
  11. If the PCM and bracket require removal, perform the following steps:
    1. Remove the PCM bracket bolts and nuts.
    2.  
    3. Remove the PCM bracket w/PCM from the studs.
    4.  

  12.  

To install:

  1. If the PCM and bracket were removed, perform the following steps:
    1. Install the PCM bracket w/PCM to the studs.
    2.  
    3. Install the PCM bracket bolts and nuts and tighten to 80 inch lbs. (9 Nm).
    4.  

  2.  
  3. Set the PCM into the bottom retainer on the bracket and push the PCM rearward, engaging the 2 top retainers.
  4.  
  5. Connect the engine wiring harness electrical connectors (1) to the PCM.
  6.  
  7. Connect the I/P wiring harness electrical connector (1) to the PCM.
  8.  
  9. Connect the negative battery cable.
  10.  
  11. If a new PCM was installed, program the PCM.
  12.  
  13. Using a scan tool, set the remaining engine oil life.
  14.  

5.3L And 6.0L Engines

Refer to Engine Control Module (ECM).

 
label.common.footer.alt.autozoneLogo