Hombre S Regular Cab 2WD L4-2.2L CPC (1998)
root cause, even when dealing with a multiple cylinder misfire. Using the information in the misfire counters, identify which cylinders are
misfiring. If the counters indicate cylinders number 1 and 4 misfired, look for a circuit or component common to both cylinders number 1 and 4
such as an open ignition coil in an electronic ignition system.
Misfire counter information is located in the Specific Eng. menu, Misfire Data sub-menu of the of the data list.
The misfire diagnostic may indicate a fault due to a temporary fault not necessarily caused by a vehicle emission system malfunction. Examples
include the following items:
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Contaminated fuel
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Running out of fuel
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Fuel fouled spark plugs
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Basic engine fault
Fuel Trim System Monitor Diagnostic Operation
This system monitors the averages of short-term and long-term fuel trim values. If these fuel trim values stay at their limits for a calibrated period
of time, a malfunction is indicated. The fuel trim diagnostic compares the averages of short-term fuel trim values and long-term fuel trim values to
rich and lean thresholds. If either value is within the thresholds, a pass is recorded. If either value is outside their thresholds, a rich or lean DTC
will set.
In order to meet OBD II requirements, the control module uses weighted fuel trim cells in order to determine the need to set a fuel trim DTC. A
fuel trim DTC can only be set if fuel trim counts in the weighted fuel trim cells exceed specifications. This means that the vehicle could have a
fuel trim problem which is causing a concern under certain conditions (i.e. engine idle high due to a small vacuum leak or rough due to a large
vacuum leak) while it operates fine at other times. No fuel trim DTC would set (although an engine idle speed DTC or O2S DTC may set).
Remember, use a scan tool in order to observe fuel trim counts while the problem is occurring. 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
The 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 The MIL is a list of components, features or
functions that could fall under this requirement.
Input Components
The control module monitors the input components for circuit continuity and out-of-range values. This includes performance checking.
Performance
checking refers to indicating a fault when the signal from a sensor does not seem reasonable (i.e. a Throttle Position (TP) sensor that indicates
high throttle position at low engine loads or MAP voltage). The input components may include but are not limited to the following sensors:
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The Vehicle Speed Sensor (VSS)
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The Crankshaft Position (CKP) sensor
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The knock Sensor (KS)
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The Throttle Position (TP) sensor
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The Engine Coolant Temperature (ECT) sensor
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The Camshaft Position (CMP) sensor
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The Manifold Absolute Pressure (MAP) sensor
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The 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 in order to enable a closed loop fuel control.
Output Components
The Output Components respond 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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The Idle Air Control (IAC) Motor
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The Control module controlled EVAP Canister Purge Valve
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The Electronic transmission controls
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The A/C relay
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The Cooling fan relay
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The VSS output
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The MIL control The Cruise control inhibit
