Dodge RAM TRUCK 1500 1995 Service Manual page 1121

B R COMPONENT DESCRIPTION/SYSTEM OPERATION—EXCEPT DIESEL 14 - 39
Refer to Group 8D, Ignition System for additional
information.
GENERATOR FIELD—PCM PIN #20—PCM OUTPUT
The powertrain control module (PCM) regulates the
charging system voltage within a range of 12.9 to
15.0 volts. Refer to Group 8A for charging system in­
formation.
INTAKE MANIFOLD AIR TEMPERATURE SENSOR—
PCM PIN #21—PCM INPUT
The intake manifold air temperature sensor is a
variable, thermistor type. It reacts to temperature
changes. At cold air temperatures, its resistance is
high. As temperatures increase, its resistance will de­
crease.
The air temperature sensor element extends into
the intake manifold air stream. It provides an input
voltage to the powertrain control module (PCM) indi­
cating intake manifold air temperature. The input
from this sensor is used along with inputs from other
sensors to determine injector pulse width. As the
temperature of the air-fuel stream in the manifold
varies, the sensor resistance will change. This will
result in a different input voltage to the PCM.
On 3.9L V-6 or 5.2/5.9L V-8 engines, the sensor is
threaded into the right-front side of the intake man­
ifold (Figs. 15 or 16).
On 8.0L V-10 engines, the sensor is threaded into
the left side of the intake manifold near the front of
the throttle body (Fig. 17).
Fig. 15 Sensor Location—3.9L V-6 Engine—Typical
THROTTLE POSITION SENSOR—PCM PIN
#22—PCM INPUT
The throttle position sensor (TPS) is located on the
left side of the throttle body on the 3.9L V-6 or 5.2/
5.9L V-8 engines (Fig. 18).
The TPS is located on the rear of the throttle body
just below the idle air control motor on the 8.0L V-10
engine (Fig. 19).
Fig. 16 Sensor Location—5.2U5.9L V-8
Engines-
Typical
Fig. 17 Sensor Location—S.OL V-10 Engine—Typical
The TPS is connected to the throttle blade shaft
and is a variable resistor. It provides the powertrain
control module (PCM) with an input signal (voltage)
that represents throttle blade position. As the posi­
tion of the throttle blade changes, the resistance of
the sensor changes.
The PCM supplies approximately 5 volts to the
sensor. The sensor output voltage (input signal to the
PCM) represents the throttle blade position. The
PCM receives an input signal voltage from the sen­
sor. This will vary in an approximate range of from 1
volt at minimum throttle opening (idle), to 4 volts at
wide open throttle. Along with inputs from other sen­
sors, the PCM uses the TPS sensor output to deter­
mine current engine operating conditions. It also will
adjust fuel injector pulse width and ignition timing.
For component testing, refer to the Diagnostics/Ser­
vice Procedures section of this group.
For removal and installation of this component, re­
fer to the Component Removal/Installation section of
Group 14, Fuel Systems.