Chrysler RAM TRUCK 2500 1994 Service Manual page 981

1 4 - 4 0 FUEL SYSTEM
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changes. A t 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. I t 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 i n the manifold
varies, the sensor resistance will change. This will
result i n 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
Fig. 16 Sensor Location—5.2U5.9L V-8. Engines—
Typical
Fig. 17 Sensor Location—8.0L V-10 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).
The TPS is connected to the throttle blade shaft
and is a variable resistor. I t 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 i n 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. I t 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.
OXYGEN (02S) SENSOR—PCM PIN #23—PCM
INPUT
PCM PINS #23 O R #41
3 J L / i . 2 L / i . S L LDC ENGINE
A single, heated 02S sensor is used on the 3.9L V-6
and the 5.2L/5.9L V-8 light duty cycle (LDC) engines.
I t is located i n the exhaust down pipe (Fig. 20). The
02S sensor provides an input voltage to the power-