8D
- 8
IGNITION
SYSTEMS
• If sync pulse signal is not present, replacement of
the camshaft position sensor is necessary. For removal or installation of ignition system com
ponents, refer to the Component Removal/Installa
tion section of this group.
For system operation and component identification,
refer to the Component Identification/System Opera
tion section of this group.
CRANKSHAFT POSITION
SENSOR
TEST
To perform a complete test of this sensor and its
circuitry, refer to the DRB II diagnostic scan tool.
Also refer to the appropriate Powertrain Diagnostics
Procedures manual. To test the sensor only, refer to
the following: The sensor is located on the top of cylinder block
near the rear of right cylinder head (Fig. 1). (1) Near the rear of intake manifold, disconnect
sensor pigtail harness connector from main wiring
harness. Fig. 1 Crankshaft Position Sensor—Typical
(2) Place an ohmmeter across terminals B and C
(Fig. 2). Ohmmeter should be set to lK-to-lOK scale
for this test. The meter reading should be open (no
resistance). Replace sensor if a low resistance is indi cated.
DISTRIBUTOR
CAP INSPECTION Remove the distributor cap and wipe it clean with
a dry lint free cloth. Visually inspect the cap for
cracks, carbon paths, broken towers, or damaged ro
tor button (Figs. 3 and 4). Also check for white de
posits on the inside (caused by condensation entering VIEW LOOKING INTO
CPS
CONNECTOR
J938D-7
Fig. 2 Sensor Connector the cap through cracks). Replace any cap that dis
plays charred or eroded terminals. The machined surface of a terminal end (faces toward rotor) will in
dicate some evidence of erosion from normal opera
tion. Examine the terminal ends for evidence of mechanical interference with the rotor tip. Fig. 3 Cap Inspection—External—Typical
DISTRIBUTOR ROTOR
Visually inspect the rotor (Fig. 5) for cracks, evi
dence of corrosion, or the effects of arcing on the
metal tip. Also check for evidence of mechanical in
terference with the cap. Some charring is normal on
the end of the metal tip. The silicone-dielectric-var nish-compound applied to the rotor tip for radio in
terference noise suppression, will appear charred.
This is normal. Do not remove the charred com pound. Test the spring for insufficient tension. Re
place a rotor that displays any of these adverse conditions.
IGNITION COIL
To perform a complete test of the ignition coil and
its circuitry, refer to the DRB II diagnostic scan tool.
•
INSTRUMENT PANEL
AND
GAUGES
8E - 3
MALFUNCTION INDICATOR (CHECK ENGINE)
Fig.
5
Distance Sensor
If
the
input from
one of the
following sensors fails
an internal Powertrain Control Module
(PCM)
self
check,
the PCM
turns
on the
Check Engine Lamp. The
PCM
then substitutes
a
modified signal
in
place
of
the one
that failed until
a
repair
is
made:
• Manifold Absolute Pressure (MAP) Sensor
• Throttle Position Sensor
• Coolant Temperature Sensor
• Battery Voltage Sense
• Battery Voltage
Too
High
Refer
to the
appropriate Powertrain Diagnostic
Test Procedures manual
for
further information.
ELECTRONIC DIGITAL CLOCK
The electronic digital clock
is in the
radio.
The
clock
and
radio each
use the
display panel built into
the radio.
A
digital readout indicates
the
time
in
hours
and
minutes whenever
the
ignition switch
is in
the
ON or ACC
position. When
the
ignition switch
is in the OFF
position
or
when
the
radio frequency
is
being displayed, time keeping
is
accurately maintained. The procedure
for
setting
the
clock varies slightly
with each radio.
The
correct procedure
is
described under
the
individual radio operating instructions
re
ferred
to in the
Owner Manual supplied with
the ve
hicle.
MESSAGE CENTER—GAS ENGINE
The message center
(Fig. 6),
located above
the
Heater-A/C controls, includes warning lamps
for the:
• brake systems (parking
and
service)
•
ABS
brakes • liftgate open (Ramcharger only)
• maintenance required.
O/D
BRAKE
(P)(7
GATE OPEN
MAINT
REQD.
J938E-54
Fig.
6
Message Center—Gas Engine
EMISSIONS
MAINTENANCE REMINDER
This system
is
designed
to act as a
reminder that
scheduled vehicle emissions maintenance should
be
performed.
It is not
intended
to
indicate
a
warn
ing
or
that
a
state
of
emergency exists which must
be
corrected
to
insure safe vehicle opera
tion.
The
components covered
by the
system include
the
EGR
system,
PCV
valve,
and
oxygen sensor. Refer
to
Group
25 -
Emissions,
for
further informa
tion.
ABS
WARNING
LIGHT
This light monitors
the ABS
Brake System. This
light will come
on
when
the
ignition
key is
turned
to
the
ON
position
and may
stay
on for as
long
as
thirty seconds.
If the ABS
light remains
on or
comes on during driving,
it
indicates that
the ABS
portion
of
the
brake system
is not
functioning. Refer
to
Group
5 -
Brakes
for
further information.
BRAKE
SYSTEM WARNING
LIGHT
The dual brake system provides
a
reserve braking
capability
in the
event
of a
failure
to a
portion
of the
hydraulic system. Failure
of
either
of the
dual sys
tem
is
indicated
by the
brake warning light which
will glow when
the
service brake pedal
is
depressed.
The light will remain
on
until
the
cause
is
corrected. The light will also come
on
when
the
parking
brake
is
applied with
the
ignition
in the ON
position.
Refer
to
Group
5 -
Brakes
for
further information.
