Nissan Maxima 1993-1998 Repair Guide

Absolute Pressure Sensor

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OPERATION



See Figure 1



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Fig. Fig. 1: Absolute pressure sensor location

The absolute pressure sensor is connected to the MAP/BARO switch solenoid valve by a hose. The sensor detects ambient barometric pressure and intake manifold pressure, and sends a voltage signal to the ECM. As pressure increases, the voltage rises. The absolute pressure sensor is not used to control the engine system. It is only used for on-board diagnosis.

TESTING



See Figures 2 and 3



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Fig. Fig. 2: Checking the absolute pressure sensor voltage at the harness connector



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Fig. Fig. 3: Checking the ground at the harness connector

  1. Remove the absolute pressure sensor with its electrical harness connected.
  2.  
  3. Disconnect the vacuum hose from the sensor.
  4.  
  5. Turn the ignition switch ON .
  6.  
  7. Backprobe the sensor connector and check output voltage, from the white wire and ground.
  8.  
  9. The voltage should be 3.2-4.8 volts.
  10.  
  11. Connect a hand powered vacuum pump and apply a vacuum of 7.87 in. Hg (26.7 kPa).
  12.  
  13. Voltage should be 1.0-1.4 volts lower than the value in Step 5.
  14.  
  15. If voltage is not within specification or does not respond as specified, check the power and ground circuits.
  16.  
  17. If the power and ground circuits are okay, the sensor may be faulty.
  18.  

REMOVAL & INSTALLATION



  1. Label and disconnect the electrical harness from the sensor.
  2.  
  3. Label and disconnect the vacuum hose from the sensor.
  4.  
  5. Remove the sensor mounting screws.
  6.  

To install:
  1. Install the sensor and tighten the screws securely.
  2.  
  3. Connect the vacuum hose to the sensor.
  4.  
  5. Connect the electrical harness to the sensor.
  6.  

 
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