Jeep 1997 Grand Cherokee Service Manual page 1246

8W - 30 - 38
DESCRIPTION AND OPERATION (Continued)
• Transmission solenoid assembly
• Upstream heated oxygen sensor
• Vehicle speed control switch
• Vehicle speed sensor
OIL PRESSURE SENSOR
The oil pressure sensor is a variable resistor. A
change in engine oil pressure changes the resistance
in the sending unit which alters the signal sensed by
the Powertrain Control Module on circuit G6. Circuit
G6 connects to cavity B23 of the PCM.
The PCM provides ground for the oil pressure sen-
sor on circuit K4. Circuit K4 connects to cavity A4 of
the PCM.
The PCM broadcasts the oil pressure data on the
CCD bus. The micro-processor in the instrument cluster
receives the signal from the CCD bus, calculates oil
pressure and adjusts the gauge needle position.
The Body Control Module (BCM) also receives the
oil pressure data broadcast by the PCM on the CCD
bus. If oil pressure drops below a calibrated pressure,
the BCM sounds an audible chime and illuminates
the oil pressure warning lamp.
OIL PRESSURE SENSOR (DIESEL)
The oil pressure sensor is a variable resistor. A
change in engine oil pressure changes the resistance
in the sending unit which alters the signal sensed by
the Powertrain Control Module on circuit G60.
The PCM provides ground for the oil pressure sen-
sor on circuit K4.
The PCM broadcasts the oil pressure data on the
CCD bus. The micro-processor in the instrument cluster
receives the signal from the CCD bus, calculates oil
pressure and adjusts the gauge needle position.
The Body Control Module (BCM) also receives the
oil pressure data broadcast by the PCM on the CCD
bus. If oil pressure drops below a calibrated pressure,
the BCM sounds an audible chime and illuminates
the oil pressure warning lamp.
WATER IN FUEL SENSOR (DIESEL)
The water in fuel sensor provides an input to the
Powertrain Control Module (PCM) on circuit G123.
The PCM provides ground for the water in fuel
sensor signal (circuit G123) through circuit K4.
FUEL INJECTORS
When the Automatic Shut Down (ASD) relay con-
tacts close, they connect circuits F5 and A142. Circuit
A142 supplies voltage to the fuel injectors. Each
injector has a separate ground circuit controlled by
the Powertrain Control Module (PCM).
Circuit K11 provides ground for injector number one.
The K11 circuit connects to cavity B4 of the PCM.
8W - 30 FUEL/IGNITION SYSTEMS
Circuit K12 provides ground for injector number two.
The K12 circuit connects to cavity B15 of the PCM.
Circuit K13 provides ground for injector number
three. The K13 circuit connects to cavity B5 of the PCM.
Circuit K14 provides ground for injector number four.
The K14 circuit connects to cavity B16 of the PCM.
Circuit K38 provides ground for injector number five.
The K38 circuit connects to cavity B6 of the PCM.
Circuit K58 provides ground for injector number six.
The K58 circuit connects to cavity B12 of the PCM.
On the 5.2L engine, circuit K17 provides ground
for injector number seven. The K17 circuit connects
to cavity B2 of the PCM.
Also on the 5.2L engine, circuit K18 provides
ground for injector number eight. The K18 circuit
connects to cavity B13 of the PCM.
HELPFUL INFORMATION
• Circuit A142 splices to supply voltage to the fuel
injectors, ignition coil, PCM, generator, and heated
oxygen sensors.
• For information about fuel injector operation,
refer to Group 14.
FUEL INJECTION PUMP (DIESEL)
The fuel injection pump used on this engine appli-
cation performs several functions. Each of these is
described as follows.
FUEL SHUT-OFF SOLENOID
Power for the fuel shut-off solenoid is supplied on
circuit A142. This circuit is HOT when the contacts
in the diesel Powertrain Control Module (PCM) relay
are CLOSED. Ground for the solenoid is controlled
by the PCM on circuit K153.
SOLENOID VALVE
Power for the solenoid is supplied on circuit A142.
This circuit is HOT when the contacts in the diesel
Powertrain
CLOSED. Ground for the solenoid is controlled by
the PCM on circuit K238.
FUEL TEMP SENSOR
Circuit K156 connects between the Powertrain
Control Module (PCM) and the fuel temperature sen-
sor. The sensor is a variable resistor. As fuel temper-
ature changes the resistance on circuit K156
changes. Ground for the sensor is supplied on circuit
K4.
CONTROL SLEEVE POSITION SENSOR
Circuit K134 connects between the Powertrain
Control Module (PCM) and the control sleeve position
sensor. This circuit is the position input to the PCM.
Circuit K57 is used for the middle tap, and circuit
K135 is used for the measure coil.
Control Module (PCM)
ZG
relay are