Dodge ram truck 3500 1996 Service Manual page 1264

14 - 30 FUEL SYSTEM B R
D E S C R I P T I O N A N D O P E R A T I O N ( C o n t i n u e d )
Fig. 2 Power Distribution Center (PDC)
should be activated, it will set a diagnostic trouble
code (DTC).
BATTERY TEMPERATURE SENSOR—PCM INPUT
Provides a signal to the PCM corresponding to the
battery temperature. Refer to Group 8G, Charging
System for additional information.
BATTERY VOLTAGE—PCM INPUT
The battery voltage input provides power to the
powertrain control module (PCM). I t also informs the
PCM what voltage level Is supplied to the ignition
coll and fuel injectors.
I f battery voltage is low, the PCM will increase
injector pulse width (period of time that the injector
is energized). This Is done to compensate for the
reduced flow through injector caused by the lowered
voltage.
FIWE
W O L I
SENSOR SUPPLY—PRIMARY
Supplies the required 5 volt power source to the
crankshaft position sensor, camshaft position sensor,
MAP sensor and throttle position sensor.
FIVE VOLT SENSOR SUPPLY—SECONDARY
Supplies the required 5 volt power source to the
transmission pressure sensor and the vehicle speed
sensor.
FUEL LEVEL SENSOR—PCM INPUT
The fuel level sensor sends a variable voltage to
the PCM to indicate fuel level. The purpose of this
feature is to prevent a false setting of misfire and
fuel system monitor trouble codes i f the fuel level is
less than 15 percent of its rated capacity.
BRAKE SWITCH—PCM INPUT
When the brake light switch is activated, the pow­
ertrain control module (PCM) receives an input indi­
cating that the brakes are being applied. After
receiving this input, the PCM maintains idle speed to
a scheduled rpm through control of the idle air con­
trol (IAC) motor. The brake switch input is also used
to operate the speed control system.
CAMSHAFT POSITION SENSOR—3.9L/5.2L/5.9L
ENGINES—PCM INPUT
A sync signal is provide by the camshaft position
sensor located in the distributor (Fig. 3). 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.
Refer to Camshaft Position Sensor in Group 8D,
Ignition System for more information.
Fig. 3 Camshaft Position Sensor—3.9L/5.2U5.9L
Engines
CAMSHAFT POSITION SENSOR—8.0L ENGINE—
PCM INPUT
A sync signal is provide by the camshaft position
sensor. The sensor is located on the side of the timing
chain case/cover (Fig. 4). The sync signal from this
sensor works in conjunction with the crankshaft posi­
tion sensor to provide the powertrain control module
(PCM) with inputs. This is done to establish and
maintain correct injector firing order.
Refer to Camshaft Position Sensor in Group 8D,
Ignition System for more information.
CRANKSHAFT POSITION SENSOR—3.9L/5.2L/5.9L
ENGINES—PCM INPUT
This sensor is a hall effect device that detects
notches in the flywheel (manual transmission) or
flexplate (automatic transmission).
This sensor is used to indicate to the powertrain
control module (PCM) that a spark and or fuel injec­
tion event is to be required. The output from this