Jeep 1997 Grand Cherokee Service Manual page 1243

ZG
DESCRIPTION AND OPERATION (Continued)
FUEL LEVEL SENSOR
The fuel level sensor is a variable resistor. Circuit
G40 provides the fuel level input to the Powertrain
Control Module (PCM). The PCM broadcasts fuel
level data on the CCD bus. The micro-processor in
the instrument cluster receives the message on the
CCD bus, calculates fuel gauge needle position and
adjusts the gauge.
VEHICLE SPEED SENSOR
Circuit K6 supplies 5 volts from the Powertrain
Control Module (PCM) to the vehicle speed sensor.
The K6 circuit connects to cavity B31 of the PCM.
Circuit G7 from the vehicle speed sensor provides
an input signal to the PCM. The G7 circuit connects
to cavity B27 of the PCM.
The PCM provides a ground for the vehicle speed
sensor signal (circuit G7) through circuit K4. Circuit
K4 connects to cavity A4 of the PCM.
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
• 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 (DIESEL)
Circuit K7 supplies voltage from the Powertrain
Control Module (PCM) to the vehicle speed sensor.
Circuit G7 from the vehicle speed sensor provides
an input signal to the PCM.
The PCM provides a ground for the vehicle speed
sensor signal (circuit G7) through circuit K4.
HEATED OXYGEN SENSORS
When the Automatic Shut Down (ASD) relay con-
tacts close, circuit A142 supplies voltage to the
upstream and downstream heated oxygen sensors.
Circuit K41 delivers the signal from the upstream
heated oxygen sensor to the Powertrain Control Mod-
ule (PCM). Circuit K41 connects to cavity A24 of the
PCM. Circuit K141 supplies the signal from the
downstream heated oxygen sensor to the PCM. Cir-
cuit K141 connects to PCM cavity A25.
8W - 30 FUEL/IGNITION SYSTEMS
The PCM provides a ground for the heated oxygen
sensor signals (circuits K41 and K141) through cir-
cuit K4. Circuit K4 connects to cavity A4 of the PCM
connector.
Circuit Z12 provides ground for the heater circuit
in each sensor.
HELPFUL INFORMATION
Circuit A142 also supplies battery voltage to the
fuel injectors, ignition coil, and generator.
Circuit K4 splices to supply ground for the signals
from the following:
• Battery temperature sensor
• Camshaft position sensor
• Crankshaft position 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
• Vehicle speed control switch
• Vehicle speed sensor
BATTERY TEMPERATURE SENSOR
The Powertrain Control Module (PCM) determines
battery temperature on circuit T222. Circuit T222
connects the PCM to the battery temperature sensor.
Circuit T222 connects to cavity C15 of the PCM. Cir-
cuit K4 provides ground for the sensor and connects
to PCM cavity A4.
CRANKSHAFT POSITION SENSOR
The Powertrain Control Module (PCM) supplies 5
volts to the crankshaft position sensor on circuit K25.
Circuit K25 connects to cavity A17 of the PCM.
The PCM receives the crankshaft position sensor
signal on circuit K27. Circuit K27 connects to cavity
A8 of the PCM.
The PCM provides a ground for the crankshaft
position sensor (circuit K27) through circuit K4. Cir-
cuit K4 connects to cavity A4 of the PCM.
HELPFUL INFORMATION
• Circuit K25 splices to supply 5 volts to the cam-
shaft position sensor, manifold absolute pressure sen-
sor and throttle position sensor.
Circuit K4 splices to supply ground for the signals
from the following:
• Battery temperature sensor
• Camshaft position sensor
• Downstream heated oxygen sensor
• Engine coolant temperature sensor
• Fuel pump module
• Intake air temperature sensor
8W - 30 - 35