Toyota 89420-06040 Sensor Assembly, Vacuum

The Manifold Absolute Pressure (MAP) sensor is key in monitoring intake manifold pressure changes, converting these into a voltage output that helps the Powertrain Control Module (PCM) control fuel delivery and ignition timing. The voltage signal from the MAP sensor to the PCM ranges from 1.9-2.1 volts at closed throttle (high vacuum) to 0.3-0.5 volts at wide open throttle (low vacuum), with slight changes based on altitude. Located on a bracket in the engine compartment, the MAP sensor can be checked by examining the reference voltage from the PCM. Disconnect the harness connector and measure voltage between terminals 3 and 1, expecting 4.5-5.5 volts with the ignition ON. If there are issues, check the PCM. Simulate conditions by reconnecting the MAP sensor, back probing terminals, disconnecting the vacuum hose, connecting a handheld vacuum pump, and applying vacuum while observing voltage increase. To replace the MAP sensor, ensure the ignition is OFF, disconnect the electrical connector and vacuum hose, remove the retaining bolt, and take out the MAP sensor. For installation, reverse these steps.