GM Astro/Safari 1985-1996 Repair Guide

Electronic Control Module (ECM)

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See Figures 1 and 2



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Fig. Fig. 1: Component locations of carbureted engine emissions devices



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Fig. Fig. 2: Engine harness connector and component locations

OPERATION



See Figure 3



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Fig. Fig. 3: ECM terminal voltages for carbureted engine

When the term Electronic Control Module (ECM) is used in this guide it will refer to the engine control computer regardless that it may be a Vehicle Control Module (VCM), Powertrain Control Module (PCM) or Engine 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 the passenger side footwell at the kick panel. The ECM can perform several on-car functions at the same time and has the ability to diagnose itself as well as other CCC system circuits.

REMOVAL & INSTALLATION



See Figure 4



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Fig. Fig. 4: ECM mounting scheme

  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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