Chrysler 1997 Stratus Convertible RHD Service Manual page 887

INTAKE TEMPERATURE INTAKE MANIFOLD SENSOR AIR MAP SENSOR
JX
DESCRIPTION AND OPERATION (Continued)
Fig. 13 Intake Air Temperature Sensor and MAP
Sensor—2.4L
Fig. 14 Intake Air Temperature Sensor and MAP
Sensor—2.5L
KNOCK SENSOR—PCM INPUT (2.0L/2.4L
ENGINES)
The knock sensor threads into the side of the cyl-
inder block in front of the starter (Fig. 15). When the
knock sensor detects a knock in one of the cylinders,
it sends an input signal to the PCM. In response, the
PCM retards ignition timing for all cylinders by a
scheduled amount.
Knock sensors contain a piezoelectric material
which sends an input voltage (signal) to the PCM. As
the intensity of the engine knock vibration increases,
the knock sensor output voltage also increases.
MANIFOLD ABSOLUTE PRESSURE (MAP)
SENSOR—PCM INPUT
The PCM supplies 5 volts direct current to the
MAP sensor. The MAP sensor converts intake mani-
fold pressure into voltage. The PCM monitors the
MAP sensor output voltage. As vacuum increases,
MAP SEN- SOR PERATURE SENSOR INTAKE THROTTLE BODY AIR TEM-
MAP sensor voltage decreases proportionately. Also,
as vacuum decreases, MAP sensor voltage increases
proportionately.
At key on, before the engine is started, the PCM
determines atmospheric air pressure from the MAP
sensor voltage. While the engine operates, the PCM
determines intake manifold pressure from the MAP
sensor voltage. Based on MAP sensor voltage and
inputs from other sensors, the PCM adjusts spark
advance and the air/fuel mixture.
The MAP sensor mounts to the intake manifold.
POWER STEERING PRESSURE SWITCH—PCM
INPUT
A pressure sensing switch is located on the power
steering gear. The switch (Fig. 16) provides an input
to the PCM during periods of high pump load and
low engine RPM; such as during parking maneuvers.
When power steering pump pressure exceeds 4137 POWER PRESSURE SWITCH
kPa (600 psi), the switch is open. The PCM increases
idle air flow through the IAC motor to prevent
engine stalling. When pump pressure is low, the
switch is closed.
Fig. 16 Power Steering Pressure Switch
STARTER MOTOR KNOCK
FUEL SYSTEM
Fig. 15 Knock Sensor
STEERING
SEN- SOR
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