Jeep 1997 Grand Cherokee Service Manual page 413

ZG
DIAGNOSIS AND TESTING (Continued)
ODOMETER AND TRIP ODOMETER
If the problem being diagnosed is related to gauge
accuracy, be certain to confirm that the problem is
with the gauge and not with an incorrect speedome-
ter pinion gear, axle ratio, or tire size. Refer to Group
21 - Transmission for more information on the speed-
ometer pinion gear. Refer to Group 8W - Wiring Dia-
grams for circuit descriptions and diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE RESTRAINT
SYSTEMS BEFORE ATTEMPTING STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL COM-
PONENT DIAGNOSIS OR SERVICE. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD RESULT
IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
Diagnosis of the vehicle speed sensor and circuit or
the Powertrain Control Module (PCM) should be per-
formed with the DRB scan tool as described in the
proper Powertrain Diagnostic Procedures manual.
Diagnosis of the odometer and trip odometer display,
the instrument cluster circuitry, the Body Control
Module (BCM), or the CCD data bus should be per-
formed with the DRB scan tool as described in the
proper Body Diagnostic Procedures manual.
OIL PRESSURE GAUGE
If the problem being diagnosed is related to gauge
accuracy, be certain to confirm that the problem is
with the gauge and not with the engine oiling system
performance. The actual engine oil pressure should
be checked with a test gauge and compared to the
instrument cluster gauge readings before you proceed
with gauge diagnosis. Refer to Group 9 - Engines for
more information. Refer to Group 8W - Wiring Dia-
grams for circuit descriptions and diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE RESTRAINT
SYSTEMS BEFORE ATTEMPTING STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL COM-
PONENT DIAGNOSIS OR SERVICE. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD RESULT
IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
Diagnosis of the oil pressure sensor and circuit or
the Powertrain Control Module (PCM) should be per-
formed with the DRB scan tool as described in the
proper Powertrain Diagnostic Procedures manual.
Diagnosis of the oil pressure gauge, the instrument
cluster circuitry, or the CCD data bus should be per-
formed with the DRB scan tool as described in the
proper Body Diagnostic Procedures manual.
INSTRUMENT PANEL SYSTEMS
SPEEDOMETER
If the problem being diagnosed is related to gauge
accuracy, be certain to confirm that the problem is
with the gauge and not with an incorrect speedome-
ter pinion gear, axle ratio, or tire size. Refer to Group
21 - Transmission for more information on the speed-
ometer pinion gear. Refer to Group 8W - Wiring Dia-
grams for circuit descriptions and diagrams.
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE RESTRAINT
SYSTEMS BEFORE ATTEMPTING STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL COM-
PONENT DIAGNOSIS OR SERVICE. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD RESULT
IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
Diagnosis of the vehicle speed sensor and circuit or
the Powertrain Control Module (PCM) should be per-
formed with the DRB scan tool as described in the
proper Powertrain Diagnostic Procedures manual.
Diagnosis of the speedometer, the instrument cluster
circuitry, or the CCD data bus should be performed
with the DRB scan tool as described in the proper
Body Diagnostic Procedures manual.
TACHOMETER
WARNING: ON VEHICLES EQUIPPED WITH AIR-
BAGS, REFER TO GROUP 8M - PASSIVE RESTRAINT
SYSTEMS BEFORE ATTEMPTING STEERING WHEEL,
STEERING COLUMN, OR INSTRUMENT PANEL COM-
PONENT DIAGNOSIS OR SERVICE. FAILURE TO
TAKE THE PROPER PRECAUTIONS COULD RESULT
IN ACCIDENTAL AIRBAG DEPLOYMENT AND POSSI-
BLE PERSONAL INJURY.
Refer to Group 8W - Wiring Diagrams for circuit
descriptions and diagrams. Diagnosis of the crank-
shaft position sensor and circuit or the Powertrain
Control Module (PCM) should be performed with the
DRB scan tool as described in the proper Powertrain
Diagnostic Procedures manual. Diagnosis of the
tachometer, the instrument cluster circuitry, or the
CCD data bus should be performed with the DRB
scan tool as described in the proper Body Diagnostic
Procedures manual.
VOLTMETER
If the problem being diagnosed is related to gauge
accuracy, be certain to confirm proper charging sys-
tem operation before considering gauge replacement.
Refer to Group 8C - Charging System for more infor-
mation. Refer to Group 8W - Wiring Diagrams for cir-
cuit descriptions and diagrams.
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