Pontiac Fiero 1984-1988 Repair Guide

Electronic Control Module (ECM)

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The ECM is the control center for the fuel injector system. It consists of three integral systems, a separate controller (ECM without the PROM), a separate calibrator (PROM) and a calpak. To allow one model of ECM to be used for many different vehicles, a device called the calibrator or Programmable Read Only Memory (PROM) is used. The PROM is located in the ECM and is very specific to the vehicle and can not be interchanged with other models as the ECM can. The CALPAK is a device used to allow fuel delivery if certain parts of the ECM should fail. The PROM and CALPAK can be removed and replaced as individual components in the ECM.

The ECM assembly is located under the rear console assembly. The console has to removed to remove the ECM assembly. The ECM diagnostic hock-up (ALDL) is also in the console assembly. To get to the Assembly Line Diagnostic Link (ALDL), lift open the ALDL door in the console.

REMOVAL & INSTALLATION





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Fig. Fig. 1 The rear console assembly must be removed to gain access to the Electronic Control Module (ECM)



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Fig. Fig. 2 Unfasten the rear console retainers ...



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Fig. Fig. 3 ... then remove the panel to gain access to the Electronic Control Module (ECM)


CAUTION
To prevent internal ECM damage, always disconnect the negative (-) battery cable before disconnecting or reconnecting the ECM fuse, jumper cables and any other related service.

  1. Disconnect the negative (-) battery cable.
  2.  
  3. Remove the rear console as follows:
  4.  
    1. Remove the shifter trim panel and move out of the way.
    2.  
    3. Open the ECM access door and remove the four rear pad attaching screws.
    4.  
    5. Remove the cigar lighter and rear console assembly.
    6.  

  5. Remove the ECM from the bracket.
  6.  
  7. Remove the ECM electrical connectors. Be careful not damage the ECM terminals.
  8.  

To install:

  1. Connect the ECM electrical connectors and install the ECM attaching screws. Torque the screws to 14 inch.lb. (1.6 Nm).
  2.  
  3. Install the rear console assembly and cigar lighter.
  4.  
  5. Install the shifter trim panel.
  6.  
  7. Reconnect the negative (-) battery cable and start the engine to check for proper operation.
  8.  

 
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