Ignition Switch And Key Lock Cylinder; Diagnosis And Testing; Automatic Shutdown (Asd) Relay Test - Jeep 1997 Grand Cherokee Service Manual

CRANKSHAFT FLYWHEEL NOTCHES POSITION SENSOR
8D - 4 IGNITION SYSTEM
DESCRIPTION AND OPERATION (Continued)
Fig. 4 Sensor Operation—4.0L 6-Cyl.Engine
rotates 180 degrees through the sync signal genera-
tor. Its signal is used in conjunction with the crank-
shaft position sensor to differentiate between fuel
injection and spark events. It is also used to synchro-
nize the fuel injectors with their respective cylinders.
When the leading edge of the pulse ring (shutter)
enters the sync signal generator, the following occurs:
The interruption of magnetic field causes the voltage
to switch high resulting in a sync signal of approxi-
mately 5 volts.
When the trailing edge of the pulse ring (shutter)
leaves the sync signal generator, the following occurs:
The change of the magnetic field causes the sync sig-
nal voltage to switch low to 0 volts.
MANIFOLD ABSOLUTE PRESSURE (MAP) SENSOR
For an operational description, diagnosis and
removal/installation procedures, refer to Group 14,
Fuel System.
ENGINE COOLANT TEMPERATURE SENSOR
For an operational description, diagnosis and
removal/installation procedures, refer to Group 14,
Fuel System.
THROTTLE POSITION SENSOR
For an operational description, diagnosis and
removal/installation procedures, refer to Group 14,
Fuel System.
FLYWHEEL
INTAKE MANIFOLD AIR TEMPERATURE SENSOR
For an operational description, diagnosis and
removal/installation procedures, refer to Group 14,
Fuel System.

IGNITION SWITCH AND KEY LOCK CYLINDER

The ignition switch is located on the steering col-
umn. The Key-In-Switch is located in the ignition
switch module. For electrical diagnosis of the Key-In-
Switch, refer to Group 8U, Chime/Buzzer Warning
Systems. For removal/installation of either the key
lock cylinder or ignition switch, refer to Ignition
Switch and Key Cylinder Removal/Installation in this
group.
On vehicles equipped with an automatic transmis-
sion, a cable connects an interlock device within the
steering column assembly to the transmission floor
shift lever. This interlock device is used to lock the
transmission shifter in the PARK position when the
key is in the LOCKED or ACCESSORY position. The
interlock device is not serviceable. If repair is neces-
sary, the steering column assembly must be replaced.
Refer to Group 19, Steering for procedures. The
shifter interlock cable can be adjusted or replaced.
Refer to Group 21, Transmissions for procedures.

DIAGNOSIS AND TESTING

AUTOMATIC SHUTDOWN (ASD) RELAY TEST

To perform a complete test of this relay and its cir-
cuitry, refer to the DRB scan tool. Also refer to the
appropriate Powertrain Diagnostics Procedures man-
ual. To test the relay only, refer to Relays—Opera-
tion/Testing in the Group 14, Fuel Systems section.
TESTING FOR SPARK AT COIL
CAUTION:
cable from a spark plug or from the distributor cap,
twist the rubber boot slightly (1/2 turn) to break it
loose (Fig. 5). Grasp the boot (not the cable) and
pull it off with a steady, even force.
(1) Disconnect the ignition coil secondary cable
from center tower of the distributor cap. Hold the
cable terminal approximately 12 mm (1/2 in.) from a
good engine ground (Fig. 6).
WARNING:
ENGINE IS CRANKING. DO NOT PUT YOUR HANDS
NEAR THE PULLEYS, BELTS OR THE FAN. DO NOT
WEAR LOOSE FITTING CLOTHING.
(2) Rotate (crank) the engine with the starter
motor and observe the cable terminal for a steady
arc. If steady arcing does not occur, inspect the sec-
When disconnecting a high voltage
BE VERY CAREFUL
ZG
WHEN THE