Corvette 1997-2005

Manifold Absolute Pressure Sensor

Print

Operation



Using the pressure and temperature data, the PCM calculates the intake air mass. It is connected to the engine intake manifold and takes readings of the absolute pressure.

Atmospheric pressure is measured both when the engine is started and when driving fully loaded, then the pressure sensor information is adjusted accordingly.

Removal & Installation



  1. Remove the oil filler cap (1).
  2.  
  3. Remove the right engine sight shield (2).
  4.  
  5. Remove the manifold absolute pressure (MAP) sensor (4).
  6.  
  7. Disconnect the electrical connector (3) for the MAP sensor.
  8.  
  9. Installation is the reverse of removal. If reusing the sensor, replace the seal.

    Click image to see an enlarged view

    Fig. MAP sensor mounting

  10.  

5.7L Engine
  1. Remove the engine sight shields, if equipped.
  2.  
  3. Remove the fuel rail assembly.
    NOTE
     Access to the MAP sensor is limited, but does not require the removal of the intake manifold.

  4.  
  5. Remove the PCV heat exchange cable fastener.
  6.  
  7. Remove the PCV hose from the throttle body and right bank port.
  8.  
  9. Release the PCV hose assembly from the mounting brackets.
  10.  
  11. Move the PCV hose assembly aside.
  12.  
  13. Disconnect the MAP sensor harness connector.
  14.  
  15. Pull the MAP sensor forward in order to release the sensor from the retainer.
  16.  
  17. Lift the MAP sensor upward.
  18.  

To install:

  1. Inspect the MAP sensor seal for damage. Replace the seal if necessary.
  2.  
  3. Lightly coat the MAP sensor seal with clean engine oil before installing the sensor.
  4.  
  5. Install the MAP sensor. Push down the sensor in order to engage the sensor into the retainer.
  6.  
  7. Connect the MAP sensor harness connector.
  8.  
  9. Position the PCV hose assembly for reassembly.
  10.  
  11. Insert the PCV hose assembly to the mounting brackets.
  12.  
  13. Install the PCV hose to the right bank port and throttle body.
  14.  
  15. Install the PCV heat exchange cable fastener. Tighten the PCV heat exchange cable fastener to 12 Nm (106 inch lbs.).
  16.  
  17. Install the fuel rail.
  18.  
  19. Install the engine sight shields.
  20.  

6.0L Engine
  1. Remove the oil filler cap (1).
  2.  
  3. Remove the right engine sight shield (2).
  4.  
  5. Remove the manifold absolute pressure (MAP) sensor (4).
  6.  
  7. Disconnect the electrical connector (3) for the MAP sensor.
  8.  
  9. Installation is the reverse of the removal procedure.
  10.  

Testing



  1. Turn ON the ignition, with the engine OFF, and remove the MAP sensor.
  2.  
  3. Install a 3 amp fused jumper wire between the 5-volt reference circuit and the corresponding terminal of the MAP sensor.
  4.  
  5. Install a jumper wire between the low reference circuit of the MAP sensor and ground.
  6.  
  7. Install a jumper wire at the MAP sensor signal circuit.
  8.  
  9. Connect a digital multimeter between the jumper wire from the MAP sensor signal circuit and ground.
  10.  
  11. Install hand vacuum pump to the MAP sensor vacuum port. Slowly apply vacuum to the sensor while observing the voltage on the multimeter. The voltage should vary between 0-5.2 volts without any spikes or dropouts.
  12.  
  13. If the voltage is not within the specified range or is erratic, replace the MAP sensor.
  14.  

 
label.common.footer.alt.autozoneLogo