Nissan Maxima 1993-1998 Repair Guide

Engine Control Module (ECM)

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OPERATION



See Figures 1 and 2



Click image to see an enlarged view

Fig. Fig. 1: The ECM is located under the dashboard behind the center console



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Fig. Fig. 2: ECM input and output schematic (VQ30DE shown)

The Engine Control Module (ECM) performs many functions. The module receives data from various engine sensors and computes the required fuel flow rate necessary to maintain correct air/fuel ratio throughout the entire engine operational range.

Based on the data received and information programmed into the ECM's memory, the ECM generates output signals to control relays, actuators and solenoids. The module automatically senses and compensates for any changes in altitude when driving the vehicle.

The ECM consists of a microcomputer, inspection lamps, a diagnostic mode selector, and connectors for signal input, signal output, power supply and ground. The ECM module is located under the center console, near the accelerator pedal.

REMOVAL & INSTALLATION



See Figures 3 and 4



Click image to see an enlarged view

Fig. Fig. 3: Tighten the ECM connector securing bolt until the gap between the orange indicators closes



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Fig. Fig. 4: Be careful not to bend or break the terminals on the ECM when installing the connector


WARNING
Electrostatic Discharge (ESD) can ruin sensitive electronic components. Always wear a grounding strap or discharge electricity stored in your body to a good ground prior to handling any electronic components.

  1. Disconnect the negative battery cable.
  2.  
  3. Remove the lower panel on the center console, if necessary.
  4.  
  5. Label and disconnect the ECM electrical harness.
  6.  
  7. Remove the ECM mounting screws.
  8.  
  9. Carefully remove the ECM from the vehicle.
  10.  

To install:
  1. Position the ECM in the vehicle and tighten the mounting screws securely.
  2.  
  3. Connect the ECM electrical harness.
  4.  
  5. Connect the negative battery cable.
  6.  
  7. Start the vehicle and verify proper operation.
  8.  
  9. Read and clear the ECM trouble code memory.
  10.  
  11. Replace the lower panel.
  12.  

 
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