Transmission Range Switch; Use Of Circuit Testing Tools; Aftermarket Electrical And Vacuum Equipment; Electrostatic Discharge Damage - Isuzu Trooper 1999 Workshop Manual

Trooper 1999
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6E–516
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
coolant temperature will be substituted for the TFT
sensor value and the transmission will operate normally.

Transmission Range Switch

IMPORTANT:
The vehicle should not be driven with the
transmission range switch disconnected; idle quality will
be affected.
The four inputs from the transmission range switch
indicate to the PCM which position is selected by the
transmission selector lever. This information is used for
ignition timing, EVAP canister purge, EGR and IAC valve
operation.
For more information on the transmission on the
transmission range switch, refer to 4L30-E Automatic
Transmission .

Vehicle Speed Sensor (VSS)

The PCM determines the speed of the vehicle by
converting a plusing voltage signal from the vehicle speed
sensor (VSS) into miles per hour. The PCM uses this
signal to operate the cruise control, speedometer, and the
TCC and shift solenoids in the transmission. For more
information on the TCC and shift solenoids, refer to
4L30-E Automatic Transmission.

Use of Circuit Testing Tools

Do not use a test light to diagnose the powertrain
electrical systems unless specifically instructed by the
diagnostic procedures. Use Connector Test Adapter Kit J
35616 whenever diagnostic procedures call for probing
connectors.
Aftermarket Electrical and Vacuum
Equipment
Aftermarket (add-on) electrical and vacuum equipment is
defined as any equipment which connects to the vehicle's
electrical or vacuum systems that is installed on a vehicle
after it leaves the factory. No allowances have been
made in the vehicle design for this type of equipment.
NOTE: No add-on vacuum equipment should be added
to this vehicle.
NOTE: Add-on electrical equipment must only be
connected to the vehicle's electrical system at the battery
(power and ground).
Add-on electrical equipment, even when installed to
these guidelines, may still cause the powertrain system to
malfunction. This may also include equipment not
connected to the vehicle electrical system such as
portable telephones and radios. Therefore, the first step
in diagnosing any powertrain problem is to eliminate all
aftermarket electrical equipment from the vehicle. After
this is done, if the problem still exists, it may be diagnosed
in the normal manner.

Electrostatic Discharge Damage

Electronic components used in the PCM are often
designed to carry very low voltage.
components are susceptible to damage caused by
electrostatic discharge. Less than 100 volts of static
electricity can cause damage to some electronic
components. By comparison, it takes as much as 4000
volts for a person to feel even the zap of a static
discharge.
There are several ways for a person to become statically
charged. The most common methods of charging are by
0008
friction and induction.
f An example of charging by friction is a person sliding
across a vehicle seat.
f Charge by induction occurs when a person with well
insulated shoes stands near a highly charged object
and momentary touches ground. Charges of the
same polarity are drained off leaving the person
highly charged with the opposite polarity.
charges can cause damage, therefore it is important
to use care when handling and testing electronic
components.
NOTE: To prevent possible electrostatic discharge
damage, follow these guidelines:
f Do not touch the PCM connector pins or soldered
components on the PCM circuit board.
f Do not touch the knock sensor module component
leads.
Electronic
TS23793
Static

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