Jeep 1997 Grand Cherokee Service Manual page 748

8W - 30 - 36
DESCRIPTION AND OPERATION (Continued)
• Manifold absolute pressure sensor
• Oil pressure sensor
• Powertrain control module
• Throttle position sensor
• Transmission solenoid assembly
• Upstream heated oxygen sensor
• Vehicle speed control switch
• Vehicle speed sensor
CRANKSHAFT POSITION SENSOR (DIESEL)
The Powertrain Control Module (PCM) supplies
voltage to the crankshaft position sensor on circuit
K24.
The PCM provides a ground for the crankshaft
position sensor (circuit K24) through circuit K4.
CAMSHAFT POSITION SENSOR
The Powertrain Control Module (PCM) supplies 5
volts to the camshaft position sensor (in distributor)
on circuit K25. Circuit K25 connects to cavity A17 of
the PCM.
The PCM receives the camshaft position sensor sig-
nal on circuit K24. Circuit K24 connects to cavity
A18 of the PCM.
The PCM provides a ground for the camshaft posi-
tion sensor signal (circuit K24) through circuit K4.
Circuit K4 connects to cavity A4 of the PCM.
HELPFUL INFORMATION
• Circuit K25 splices to supply 5 volts to the
crankshaft position sensor, manifold absolute pres-
sure sensor, and throttle position sensor.
Circuit K4 splices to supply ground for the signals
from the following:
• Battery temperature sensor
• Crankshaft position sensor
• Downstream heated oxygen sensor
• Engine coolant temperature sensor
• Fuel pump module
• Intake air temperature sensor
• Manifold absolute pressure sensor
• Oil pressure sensor
• Powertrain control module
• Throttle position sensor
• Transmission solenoid assembly
• Upstream heated oxygen sensor
• Vehicle speed control switch
• Vehicle speed sensor
ENGINE COOLANT TEMPERATURE SENSOR
The engine coolant temperature sensor provides an
input to the Powertrain Control Module (PCM) on
circuit K2. From circuit K2, the engine coolant tem-
perature sensor draws up to 5 volts from the PCM.
The sensor is a variable resistor. As coolant temper-
ature changes, the resistance in the sensor changes,
8W - 30 FUEL/IGNITION SYSTEMS
causing a change in current draw. The K2 circuit
connects to cavity A16 of the PCM.
The PCM provides a ground for the engine coolant
temperature sensor signal (circuit K2) through circuit
K4. Circuit K4 connects to cavity A4 of the PCM con-
nector.
HELPFUL INFORMATION
Circuit K4 splices to supply ground for the signals
from the following:
• Battery temperature sensor
• Camshaft position sensor
• Crankshaft position sensor
• Downstream heated oxygen sensor
• Fuel pump module
• Intake air temperature sensor
• Manifold absolute pressure sensor
• Oil pressure sensor
• Powertrain control module
• Throttle position sensor
• Transmission solenoid assembly
• Upstream heated oxygen sensor
• Vehicle speed control switch
• Vehicle speed sensor
ENGINE COOLANT TEMPERATURE SENSOR
(DIESEL)
The Engine Coolant Temperature (ECT) sensor on
this engine application is a dual function sensor. It
provides a engine coolant temperature input to the
Powertrain Control Module (PCM) on Circuits K2
and Circuit K222.
Ground for the sensor is supplied on circuit K4.
The sensor is a variable resistor. As engine coolant
temperature changes the resistance on the K4 circuit
changes.
EVAPORATIVE SYSTEM LEAK DETECTION PUMP
Vehicle built for sale in the State of California are
equipped with an evaporative system leak detection
pump.
When the ignition switch is in the START or RUN
position, it connects circuit A1 from fuse 8 in the
Power Distribution Center (PDC) to circuit A21. Cir-
cuit A21 powers circuit F99 through PDC fuse 18.
Circuit F99 feeds the leak detection pump.
On circuits J96 and J95, the PCM operates the
leak detection pump. Circuit J96 connects to cavity
C14 of the PCM. Circuit J95 connects to PCM cavity
C10.
THROTTLE POSITION SENSOR
From the Powertrain Control Module (PCM), cir-
cuit K25 supplies 5 volts to the throttle position sen-
sor (TPS). Circuit K25 connects to cavity A17 of the
PCM.
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