Dodge RAM TRUCK 1500 1995 Service Manual page 1127

B R — — — — COMPONENT DESCRIPTION/SYSTEM OPERATION—EXCEPT DIESEL 14 - 45
TEMPERATURE SENSOR J9414-46
Fig. 30 Transmission Temperature Sensor
Location—Typical
TACHOMETER—PCM PIN #43—PCM OUTPUT
The powertrain control module (PCM) supplies en­
gine rpm values to the instrument cluster mounted
tachometer (if equipped). Refer to Group 8E for ta­
chometer information.
CAMSHAFT POSITION SENSOR—PCM PIN
#44—PCM INPUT
A fuel sync signal is provided by the camshaft po­
sition sensor. The sync signal from this sensor works
in conjunction with the crankshaft position sensor to
provide the powertrain control module (PCM) with
inputs. This is done to establish and maintain correct
injector firing order. The sensor is located in the dis­
tributor (Fig. 31-3.9L/5.2L/5.9L engine), or in the
timing chain case/cover on the left-front side of the
engine (Fig. 32-8.0L V-10 engine).
Refer to Camshaft Position Sensor in Group 8D, Ig­
nition System for more information.
Fig. 31 Camshaft Position Sensor—3.9U5.2L/5.9L
Engine
CAMSHAFT \
Fig. 32 Camshaft Position Sensor—S.OL ¥-10 Engine
DATA LINK CONNECTOR—PCM PIN #45—PCM
INPUT
Refer to Data Link Connector-PCM PIN
#25-PCM Output for information.
CCD BUS(-)—PCM PIN #46—PCM OUTPUT
Various modules exchange information through a
communications port called the CCD BUS(-).
VEHICLE SPEED SENSOR—PCM PIN #47—PCM
INPUT
The speed sensor (Fig. 33) is located in the exten­
sion housing of the transmission (2WD) or on the
transfer case extension housing (4WD). The sensor
input is used by the powertrain control module
(PCM) to determine vehicle speed and distance trav­
eled.
The speed sensor generates 8 pulses per sensor
revolution. These signals, in conjunction with a
closed throttle signal from the throttle position sen­
sor, indicate a closed throttle deceleration to the
PCM. When the vehicle is stopped at idle, a closed
throttle signal is received by the PCM (but a speed
sensor signal is not received).
Under deceleration conditions, the PCM adjusts the
idle air control (IAC) motor to maintain a desired
MAP value. Under idle conditions, the PCM adjusts
the IAC motor to maintain a desired engine speed.
In addition to determining distance and vehicle
speed, the output from the sensor is used to help con­
trol:
• Speed control operation
• Transmission overdrive operation
• Transmission torque converter electrical operation
© Idle air control (IAC) motor for engine idle speed
• Fuel injector pulse width