Park Avenue V6-3.8L SC VIN 1 (2005)
Manifold Pressure/Vacuum Sensor: Testing and Inspection
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR DIAGNOSIS
CIRCUIT DESCRIPTION
The MAP sensor responds to changes in intake manifold pressure which gives an indication of the engine load. The MAP sensor has a 5-volt reference
circuit, a low reference circuit, and a signal circuit. The PCM supplies 5 volts to the MAP sensor on the 5-volt reference circuit and provides a ground
on the low reference circuit. The MAP sensor provides a signal to the PCM on the MAP sensor signal circuit, which is relative to the pressure changes
in the manifold. With low MAP, such as during idle or deceleration, the PCM should detect a low MAP sensor signal voltage. With high MAP, such
as WOT, the PCM should detect a high MAP sensor signal voltage. This MAP sensor will indicate pressure between 8-208 kPa. The MAP sensor is
also used in order to calculate the BARO when the ignition switch is turned ON, with the engine OFF. The PCM monitors the MAP sensor signal for
voltage outside of the normal range. If the PCM detects a MAP sensor signal voltage that is excessively low, DTC P0107 sets. If the PCM detects a
MAP sensor signal voltage that is excessively high, DTC P0108 sets.
DIAGNOSTIC AIDS
Poor idle characteristics may be caused by uncontrolled fueling due to an open or high resistance in the HO2S 1 low signal circuit. Before replacing
any component, ensure that this condition does not exist.
TEST DESCRIPTION
