DaimlerChrysler Jeep Grand Cherokee 2002, Руководство по обслуживанию

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4.2.2 VEHICLE PREPARATION FOR
TESTING
Make sure the vehicle being tested has a fully
charged battery. If it does not, false diagnostic codes
or error messages may occur.
4.2.3 SERVICING SUB-ASSEMBLIES
Some components of the powertrain system are
intended to be serviced as an assembly only. At-
tempting to remove or repair certain system sub-
components may result in personal injury and/or
improper system operation. Only those components
with approved repair and installation procedures in
the service manual should be serviced.
4.2.4 DRBIII
T
SAFETY INFORMATION
WARNING: EXCEEDING THE LIMITS OF THE
DRBIII
T
MULTIMETER IS DANGEROUS. IT
CAN EXPOSE YOU TO SERIOUS OR
POSSIBLY FATAL INJURY. CAREFULLY
READ AND UNDERSTAND THE CAUTIONS
AND SPECIFICATION LIMITS.
Follow the vehicle manufacturer’s service specifi-
cations at all times.
• Do not use the DRBIII
t
if it has been damaged.
•
Do not use the test leads if the insulation is
damaged or if metal is exposed.
• To avoid electrical shock, do not touch the test
leads, tip or the circuit being tested.
• Choose the proper range and function for the
measurement. Do not try voltage or current mea-
surements that may exceed the rated capacity.
•
Do not exceed the limits shown in the table below:
FUNCTION INPUT LIMIT
Volts 0-500 peak volts AC
0-500 volts DC
Ohms (Resistance)* 0-1.12 megohms
Frequency Measure
Frequency Generated 0-10 kHz
Temperature -58 - +1100°F
-50 - +600°C
* Ohms cannot be measured if voltage is present.
Ohms can be measured only in a non-powered
circuit.
• Voltage between any terminal and ground must
not exceed 500v DC or 500v peak AC.
•
Use caution when measuring voltage above 25v
DC or 25v AC.
• The circuit being tested must be protected by a 10
amp fuse or circuit breaker.
• Use the low current shunt to measure circuits up
to 10 amps. Use the high current shunt to mea-
sure circuits exceeding 10 amps.
•
When testing for the presence of voltage or cur-
rent, make sure the meter is functioning cor-
rectly. Take a reading of a known voltage or
current before accepting a zero reading.
• When measuring current, connect the meter in
series with the load.
• Disconnect the live test lead before disconnecting
the common test lead.
4.3 WARNINGS AND CAUTIONS
4.3.1 ROAD TEST WARNINGS
Some complaints will require a test drive as part
of the repair verification procedure. The purpose of
the test drive is to try to duplicate the diagnostic
code or symptom condition.
CAUTION: Before road testing a vehicle, be
sure that all components are reassembled.
During the test drive, do not hang the DRBIII
T
from the rear view mirror. Do not attempt to
read the DRBIII
T
while driving. Have an
assistant available to operate the DRBIII
T
.
4.3.2 VEHICLE DAMAGE CAUTIONS
Before disconnecting any control module, make
sure the ignition is off. Failure to do so could
damage the module. When testing voltage or circuit
integrity at any control module, use the terminal
side (not the wire end) of the harness connector. Do
not probe through the insulation; this will damage
it and eventually cause it to fail because of corro-
sion.
Be careful when performing electrical test so as to
prevent accidental shorting of terminals. Such a
mistake can damage fuses or components. Also, a
second code could be set, making diagnosis of the
original problem more difficult.
5.0 REQUIRED TOOLS AND
EQUIPMENT
DRBIII
t
(diagnostic read-out box) scan tool
vacuum gauge
ammeter
ohmmeter
voltmeter
jumper wires and probes
oscilloscope
8
GENERAL INFORMATION
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