Circuit Description
The manifold absolute pressure (MAP) sensor measures the changes in the intake manifold pressure which result from engine load, intake manifold vacuum, and RPM changes. The MAP sensor converts these changes into a voltage output. The electronic control module (ECM) sends a 5-volt reference voltage to the MAP sensor. As the intake manifold pressure changes, the output voltage of the MAP sensor also changes. A low voltage, high vacuum, output of 1-2 volts is present at idle. A high voltage, low vacuum, output of 4-4.8 volts is present at wide open throttle. The MAP sensor is also used under certain conditions to measure barometric pressure. This allows the ECM to make adjustments for altitude changes. The ECM uses the MAP sensor for fuel delivery and ignition timing changes.
Step | Action | Values | Yes | No |
|---|---|---|---|---|
1 |
Is the difference in the 2 voltage reading less than the value specified? | 0.4 V | Go to Step 2 | Go to Step 5 |
2 |
Is the difference in voltage readings more than the value specified? | 1.5 V | System OK | Go to Step 3 |
3 | Inspect the MAP sensor connector terminals. Is the problem found? | -- | Go to Step 4 | Go to Step 5 |
4 | Repair the MAP sensor connector terminals as needed. Is the repair complete? | -- | System OK | -- |
5 | Replace the MAP sensor. Refer to Manifold Absolute Pressure Sensor Replacement . Is the repair complete? | -- | System OK | -- |
