GM Full Size Vans 1987-1997 Repair Guide

Electronic Control Module (ECM)

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OPERATION



See Figure 1

When the term Electronic Control Module (ECM) is used in this guide, it refers to the engine control computer, whether it is a Vehicle Control Module (VCM), Powertrain Control Module (PCM) or Electronic Control Module (ECM).

The ECM is a reliable solid state computer, protected in a metal box. It is used to monitor and control all the functions of the Computer Command Control (CCC) system and is located in one of several places in the passenger compartment (refer to the component location diagrams in this section). The ECM can perform several on-vehicle functions at the same time and has the ability to diagnose itself as well as other CCC system circuits.



Click image to see an enlarged view

Fig. Fig. 1: Typical component locations of emission control devices on carburetor equipped models

REMOVAL & INSTALLATION



  1. Disconnect the negative battery cable.
  2.  
  3. Disengage the connectors from the ECM.
  4.  
  5. Remove the ECM mounting hardware.
  6.  
  7. Remove the ECM from the passenger compartment.
  8.  
  9. Installation is the reverse of removal.
  10.  

 
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