Jeep 1996 Grand Cherokee Service Manual page 540

ZJ
DESCRIPTION AND OPERATION
AUTOMATIC SHUT DOWN (ASD) RELAY . . . . . . . 1
BATTERY FEED . . . . . . . . . . . . . . . . . . . . . . . . . . 1
BATTERY TEMPERATURE SENSOR . . . . . . . . . . 2
CAMSHAFT POSITION SENSOR . . . . . . . . . . . . . 3
CCD BUS . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 5
CRANKSHAFT POSITION SENSOR . . . . . . . . . . . 3
DATA LINK CONNECTOR . . . . . . . . . . . . . . . . . . . 1
DUTY CYCLE EVAP\PURGE SOLENOID . . . . . . . 5
ENGINE COOLANT TEMPERATURE SENSOR . . . 3
EVAPORATIVE SYSTEM LEAK DETECTION
PUMP . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3
FUEL INJECTORS . . . . . . . . . . . . . . . . . . . . . . . . 4
FUEL PUMP MODULE . . . . . . . . . . . . . . . . . . . . . 2
DESCRIPTION AND OPERATION
IGNITION SWITCH
Circuit A1 from fuse 8 in the Power Distribution
Center (PDC) powers four different circuits through
the ignition switch. When the ignition switch is in
the START or RUN position, it connects circuit A1 to
circuit A21.
In the ACCESSORY or RUN position, the ignition
switch connects to circuit A31. In the START posi-
tion, the ignition switch connects circuit A1 to circuit
A41. When the ignition switch is in the RUN position
it connects circuit A1 to circuit A22.
Also in the START position, the case grounded
ignition switch grounds circuit G9 from the brake
warning switch.
BATTERY FEED
Circuit F5 from fuse 20 in the Power Distribution
Center (PDC) supplies battery voltage to cavity A22
of the Powertrain Control Module (PCM). Circuit A7
from PDC fuse 15 also powers the PDC at cavity
A14.
HELPFUL INFORMATION
Circuit F5 also supplies power to the contact sides
of the Automatic Shut Down (ASD) relay.
GROUND
Circuit Z12 connects to cavities A31 and A32 of the
PCM. The Z12 circuit provides ground for PCM inter-
nal drivers that operate high current devices like the
injectors and ignition coil.
8W - 30 FUEL/IGNITION SYSTEMS
8W-30 FUEL/IGNITION SYSTEMS
page
INDEX
FUEL PUMP RELAY . . . . . . . . . . . . . . . . . . . . . . . 2
GROUND . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1
HEATED OXYGEN SENSORS . . . . . . . . . . . . . . . 2
IDLE AIR CONTROL (IAC) MOTOR . . . . . . . . . . . 5
IGNITION COIL . . . . . . . . . . . . . . . . . . . . . . . . . . 5
IGNITION SWITCH . . . . . . . . . . . . . . . . . . . . . . . . 1
INTAKE AIR TEMPERATURE SENSOR . . . . . . . . . 4
MANIFOLD ABSOLUTE PRESSURE SENSOR . . . 4
OIL PRESSURE SENSOR . . . . . . . . . . . . . . . . . . 4
THROTTLE POSITION SENSOR . . . . . . . . . . . . . 3
VEHICLE SPEED SENSOR . . . . . . . . . . . . . . . . . 2
SCHEMATICS AND DIAGRAMS
WIRING DIAGRAM INDEX . . . . . . . . . . . . . . . . . . 5
Internal to the PCM, the ground circuit connects to
the PCM sensor return circuit (from circuit K4).
HELPFUL INFORMATION
• If the system loses ground for the Z12 circuits,
the vehicle will not operate. Check the connection at
the ganged-ground circuit eyelet.
DATA LINK CONNECTOR
Circuit A250 from fuse 11 in the Power Distribu-
tion Center (PDC) powers circuit F75 through fuse 7
in the junction block. Circuit F75 supplies battery
voltage to the data link connector.
Circuit D84 connects to cavity C29 of the PCM.
Circuit D84 is the SCI transmit circuit for the Pow-
ertrain Control Module (PCM). Circuit D83 connects
to cavity C27 of the PCM and cavity A3 of the Con-
troller- Anti Lock Brakes. Circuit D83 is the SCI
receive circuit for the PCM.
Circuits D98 and D99 from the speed proportional
steering module connect to the data link connector.
Circuits Z1 and Z2 provide ground for the data link
connector.
AUTOMATIC SHUT DOWN (ASD) RELAY
When the ignition switch is in either the START or
RUN position, it connects circuit A1 from fuse 8 in
the Power Distribution Center (PDC) to circuit A21.
Circuit A21 powers circuit F99 through PDC fuse 18.
Circuit F99 feeds the coil side of the Automatic Shut
Down (ASD) relay. The Powertrain Control Module
(PCM) provides ground for the relay on circuit K900.
Circuit K900 connects to cavity C3 of the PCM.
8W - 30 - 1
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