Dodge RAM TRUCK 1500 1995 Service Manual page 577

8W-30 FUEL/IGNITION—GASOLINE ENGINES
8W - 30 - 5
© Engine coolant temperature sensor
© Vehicle speed sensor
MANIFOLD ABSOLUTE PRESSURE SENSOR
From the Powertrain Control Module (PCM), cir­
cuit KB supplies 5 volts to the manifold absolute
pressure (MAP) sensor. Circuit K6 connects to cavity
6 of the PCM.
Circuit Kl delivers the MAP signal to the PCM.
Circuit Kl connects to cavity 1 of the PCM.
The PCM provides a ground for the MAP sensor
signal (circuit Kl) through circuit K4. Circuit K4 con­
nects to cavity 4 of the PCM.
HELPFUL INFORMATION
Refer to Group 14 for MAP sensor operation.
Circuit K6 splices to supply 5 volts to the throttle
position sensor.
Circuit K4 splices to supply ground for the signals
from the following:
• Heated oxygen sensor(s)
• Camshaft position sensor
© Crankshaft position sensor
• Intake air temperature sensor
• Throttle position sensor
© Engine coolant temperature sensor
o Vehicle speed sensor
INTAKE AIR TEMPERATURE SENSOR
The intake air temperature sensor provides an in­
put to the Powertrain Control Module (PCM) on cir­
cuit K21. Circuit K21 connects to cavity 21 of the
PCM.
From circuit K21, the intake air temperature sen­
sor draws voltage from the PCM. The sensor is a
variable resistor. As intake air temperature changes,
the resistance in the sensor changes, causing a
change in current draw.
The PCM provides a ground for the intake air tem­
perature sensor signal (circuit K21) through circuit
K4. Circuit K4 connects to cavity 4 of the PCM.
HELPFUL INFORMATION
Circuit K4 splices to supply ground for the signals
from the following:
• Heated oxygen sensor(s)
© Camshaft position sensor
• Crankshaft position sensor
• Throttle position sensor
® Manifold absolute pressure sensor
• Engine coolant temperature sensor
© Vehicle speed sensor
PARK/NEUTRAL POSITION SWITCH
When closed, the case-grounded PARK/NEUTRAL
position switch provides a ground path on circuit T41
for the coil -side of the starter motor relay. Circuit
T41 splices to cavity 30 of the Powertrain Control
Module (PCM). The PARK/NEUTRAL position switch
provides an input to the PCM.
TCC SOLENOID
The TCC solenoid and overdrive solenoid are
molded together. They are only used on automatic
transmissions. The Powertrain Control Module
(PCM) operates the TCC solenoid by providing a
ground path on circuit K54. Circuit K54 connects to
PCM cavity 54.
When the ignition switch is in the START or RUN
position, it connects circuit Al from, fuse 3 in the
PDC to circuit A21. Circuit A21 powers circuit F18
through fuse 9 in the fuse block. Circuit F18 supplies
battery voltage to the TCC solenoid.
UPSHIFT LAMP
On vehicles equipped with a manual transmission,
the Powertrain Control Module (PCM) provides a
ground path for the instrument cluster upshift lamp
on circuit K54. Circuit F14 provides battery voltage
to the lamp.
OVERDRIVE SOLENOID
The overdrive solenoid and TCC solenoid are
molded together. They are only used on automatic
transmissions. The Powertrain Control Module
(PCM) operates the overdrive solenoid by providing a
ground path on circuit T60. Circuit T60 connects to
PCM cavity 55.
When the ignition switch is in the START or RUN
position, it connects circuit Al from fuse 3 in the
PDC to circuit A21. Circuit A21 powers circuit F18
through fuse 9 in the fuse block. Circuit F18 supplies
battery voltage to the overdrive solenoid.
EGR SOLENOID
The Powertrain Control Module (PCM), operates
the Exhaust Gas Recirculation (EGR) solenoid by
providing a ground path on circuit K35. Circuit K35
connects to PCM cavity 35.
When the ignition switch is in the START or RUN
position, it connects circuit Al from fuse 3 in the
PDC to circuit A21. Circuit A21 powers circuit F18
through fuse 9 in the fuse block. Circuit F18 supplies
battery voltage to the EGR solenoid.
EVAP/PURGE SOLENOID
The powertrain control module (PCM) operates the
EVAP/purge solenoid by providing a ground path on
circuit K52. Circuit K52 connects to PCM cavity 52.
: When the ignition switch is in the START or RUN
position, it connects circuit Al from fuse 3 in the
PDC to circuit A21. Circuit A21 powers circuit F18
through fuse 9 in the fuse block. Circuit F18 supplies
battery voltage to the EVAP/Purge solenoid.