Isuzu 2000 Trooper UX, Руководство по ремонту

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6E–39
TROOPER 6VE1 3.5L ENGINE DRIVEABILITY AND EMISSIONS
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Inspect all vacuum hoses for pinches, cuts,
disconnections, and proper routing.
D
Inspect hoses that are difficult to see behind other
components.
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Inspect all wires in the engine compartment for proper
connections, burned or chafed spots, pinched wires,
contact with sharp edges or contact with hot exhaust
manifolds or pipes.
Basic Knowledge of Tools Required
NOTE: Lack of basic knowledge of this powertrain when
performing diagnostic procedures could result in an
incorrect diagnosis or damage to powertrain
components. Do not attempt to diagnose a powertrain
problem without this basic knowledge.
A basic understanding of hand tools is necessary to effec-
tively use this section of the Service Manual.
Serial Data Communications
Class II Serial Data Communications
Government regulations require that all vehicle
manufacturers establish a common communication
system. This vehicle utilizes the “Class II”
communication system. Each bit of information can have
one of two lengths: long or short. This allows vehicle
wiring to be reduced by transmitting and receiving
multiple signals over a single wire. The messages carried
on Class II data streams are also prioritized. If two
messages attempt to establish communications on the
data line at the same time, only the message with higher
priority will continue. The device with the lower priority
message must wait. The most significant result of this
regulation is that it provides Scan tool manufacturers with
the capability to access data from any make or model
vehicle that is sold.
The data displayed on other Scan tools will appear the
same, with some exceptions. Some Scan tools will only
be able to display certain vehicle parameters as values
that are a coded representation of the true or actual value.
On this vehicle the Scan tool displays the actual values for
vehicle parameters. It will not be necessary to perform
any conversions from coded values to actual values.
On-Board Diagnostic (OBD II)
On-Board Diagnostic Tests
A diagnostic test is a series of steps, the result of which is
a pass or fail reported to the diagnostic executive. When
a diagnostic test reports a pass result, the diagnostic
executive records the following data:
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The diagnostic test has been completed since the last
ignition cycle.
D
The diagnostic test has passed during the current
ignition cycle.
D
The fault identified by the diagnostic test is not
currently active.
When a diagnostic test reports a fail result, the diagnostic
executive records the following data:
D
The diagnostic test has been completed since the last
ignition cycle.
D
The fault identified by the diagnostic test is currently
active.
D
The fault has been active during this ignition cycle.
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The operating conditions at the time of the failure.
Remember, a fuel trim DTC may be triggered by a list of
vehicle faults. Make use of all information available (other
DTCs stored, rich or lean condition, etc.) when
diagnosing a fuel trim fault.
Comprehensive Component Monitor
Diagnostic Operation
Comprehensive component monitoring diagnostics are
required to monitor emissions-related input and output
powertrain components. The
CARB OBD II
Comprehensive Component Monitoring List Of
Components Intended To illuminate MIL is a list of
components, features or functions that could fall under
this requirement.
Input Components:
Input components are monitored for circuit continuity and
out-of-range values. This includes rationality checking.
Rationality checking refers to indicating a fault when the
signal from a sensor does not seem reasonable, i.e.
Throttle Position (TP) sensor that indicates high throttle
position at low engine loads or MAP voltage. Input
components may include, but are not limited to the
following sensors:
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Vehicle Speed Sensor (VSS)
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Crankshaft Position (CKP) sensor
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Throttle Position (TP) sensor
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Engine Coolant Temperature (ECT) sensor
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Camshaft Position (CMP) sensor
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Manifold Absolute Pressure (MAP) sensor
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Mass Air Flow (MAF) sensor
In addition to the circuit continuity and rationality check,
the ECT sensor is monitored for its ability to achieve a
steady state temperature to enable closed loop fuel
control.
Output Components:
Output components are diagnosed for proper response to
control module commands. Components where
functional monitoring is not feasible will be monitored for
circuit continuity and out-of-range values if applicable.
Output components to be monitored include, but are not
limited to, the following circuits:
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Control module controlled EVAP Canister Purge
Valve
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Electronic Transmission controls
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A/C relays
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Cooling fan relay
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VSS output
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MIL control