The MAP sensor measures manifold vacuum using a frequency. This gives the computer control module information on engine load. It is used as a barometric sensor for altitude compensation, updating the control module during key ON, engine OFF and every wide-open throttle. The ECU uses the MAP sensor for spark advance, EGR flow and air/fuel ratio.
- Disconnect the vacuum supply hose from the MAP sensor.
- Connect a suitable vacuum pump to the MAP sensor and apply 18 in. Hg (61 kPa) of vacuum.
- If the MAP sensor does not hold vacuum, it must be replaced.
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Disengage the electrical connector and the vacuum line from the sensor.
- Unfasten the sensor mounting bolts, then remove the sensor.
- Installation is the reverse of the removal procedure.