Chart C-1D Manifold Absolute Pressure (MAP) Output Check

Chart C-1D Manifold Absolute Pressure (MAP) Sensor Output Check:

Manifold Absolute Pressure (MAP) Sensor Output Check:

CIRCUIT DESCRIPTION
The Manifold Absolute Pressure (MAP) sensor measures resistance changes based, on manifold vacuum. The Powertrain Control Module (PCM) supplies a 5 volt reference and a ground. The MAP sensor voltage varies from 1.0 to 1.5V at idle (high vacuum) to 4.0 - 4.5V at wide open throttle (low vacuum). The MAP sensor is also used, under certain conditions, to measure barometric pressure, allowing the PCM to make adjustments for altitude changes. The PCM uses the MAP sensor to control fuel delivery and ignition timing.

CHART TEST DESCRIPTION
Number(s) below refer to circled number(s) on the diagnostic chart.

1. When comparing scan readings to a known good vehicle, it is important to compare vehicles that use a MAP sensor having the same color insert and the same "Hot Stamped" number. See image.
2. Applying 34 kPa (10" Hg) vacuum to the MAP sensor should result in voltage readings of 1.5 to 2.1 volts less than the voltage in Step 1. Upon applying vacuum to the sensor, the change in voltage should be instantaneous. A slow voltage change indicates a faulty sensor.
3. Check vacuum seal to sensor for leaking or restriction.
4. Remove sensor from the intake plenum and twist sensor (by hand only) to check for intermittent connection. Output changes greater than 0.10 volt indicate a faulty sensor or connection. If OK, replace sensor.


NOTICE: Make sure electrical connector remains securely fastened.