Nissan Sentra/Pulsar/NX 1982-1996 Repair Guide

Engine Control Module (ECM)

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OPERATION



The ECM consists of a microcomputer, inspection lamps, a diagnostic mode selector and connectors for signal input and output, and for power supply. The unit has control of the injected fuel amount, ignition timing, mixture ratio feedback, idle speed, fuel pump operation, mixture heating, AIV operation, and EGR and canister purge operation.

TESTING



There are no methods currently available to test the ECM in the field. Most testing of the ECM, usually involves testing the components associated with the ECM and if all components are okay, substituting a know good unit is the common practice.

REMOVAL & INSTALLATION



1984-90 Vehicles
  1. Disconnect the negative battery cable.
  2.  
  3. Locate the ECM under either front seat.
  4.  
  5. Slide the seat assembly fully in either direction in order to gain access.
  6.  
  7. Disconnect the ECM harness connectors.
  8.  
  9. Remove the bolts securing the ECM to the vehicle floor.
  10.  

To install:
  1. Position the ECM on the vehicle floor. Install and tighten the retaining bolts.
  2.  
  3. Connect the electrical connectors to the ECM.
  4.  
  5. Connect the negative battery cable.
  6.  

1991-96 Vehicles
  1. Disconnect the negative battery cable.
  2.  
  3. Remove the center shift console side undercover panels as outlined in General Information & Maintenance 0.
  4.  
  5. Disconnect the ECM harness connectors.
  6.  
  7. Remove the bolts securing the ECM to the vehicle floor.
  8.  

To install:
  1. Position the ECM on the vehicle floor. Install and tighten the retaining bolts.
  2.  
  3. Connect the ECM harness connector to the ECM monitor.
  4.  
  5. Position and secure the center shift console side undercover panels.
  6.  
  7. Connect the negative battery cable.
  8.  

 
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