The Manifold Absolute Pressure (MAP) sensor measures and converts intake manifold vacuum into a voltage signal. The higher the vacuum, the lower the voltage signal that is sent to the ECM/PCM. The range of operation of the MAP sensor varies from approximately 0.5-3.0 volts. The ECM/PCM compares the Throttle Position (TP) sensor with the MAP sensor readings to verify proper operation. Any discrepancy between the MAP sensor and the TP sensor is likely to trigger the Malfunction Indicator Lamp (MIL). The MAP sensor provides the ECM/PCM information on engine load.
- Check the connection at the MAP sensor connector.
- Check the terminals within the connector for corrosion or poor contacts causing high resistance.
- Repair or replace electrical connections as necessary.
- If code three is detected, an electrical problem in the system may be present.
- Remove the electrical connector from the MAP sensor.
- Turn the ignition key to the ON position.
- Connect the positive lead of a voltmeter to the terminal No. 1, the leftmost electrical terminal.
- Connect the negative probe to the terminal No. 2, the middle electrical terminal harness. Do not probe the MAP sensor side.
- With the voltmeter connected properly there should be a 5 volts reference signal.
REMOVAL & INSTALLATION
- Disconnect the negative battery cable.
- Disconnect the MAP sensor vacuum lines.
- Remove the mounting screws from the MAP sensor.
- Remove the MAP sensor.
- Installation is the reverse of removal.