Hombre S Regular Cab 2WD L4-2.2L CPC (1998)
Engine Control Module: Description and Operation
Powertrain Control Module Description Part 1
The Control Module refers to the Powertrain Control Module (PCM) and the Vehicle Control Module (VCM). The control module is designed to
maintain exhaust emission levels to Federal or California standards while providing excellent driveability and fuel efficiency. Review the
components and wiring diagrams in order to determine which systems are controlled by each specific control module. The control module
monitors numerous engine and vehicle functions. The control module controls the following operations:
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Fuel control
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Ignition Control (IC)
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Knock Sensor (KS) system
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Automatic transmission shift functions
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Cruise Control Enable
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Generator
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Evaporative Emission (EVAP) Purge
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A/C Clutch Control
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Cooling Fan Control
Control Module Function
The Control Module supplies a buffered voltage to various sensors and switches. The input and output devices in the control module include an
analog to digital converters, signal buffers, counters, and special drivers. The Control Module controls most components with electronic switches
which complete a ground circuit when turned ON. These switches are arranged in groups of 4 and 7 called one of the following:
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Quad Driver Module
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Output Driver Modules
The surface mounted Quad Driver Module can independently control up to 4 outputs (Control Module) terminals. The Output Driver Modules
can independently control up to 7 outputs. Not all outputs are always used.
Use of Circuit Testing Tools
Do not use a test lamp in order to diagnose the Powertrain electrical Systems unless specifically instructed by the diagnostic procedures. Use the
Connector Test Adapter Kit, J 35616 whenever the diagnostic procedures call for probing any of the connectors.
Control Module Service Precautions
The control module is designed to withstand the normal current draws that are associated with the vehicle operations. Avoid overloading any
circuit. When testing for opens or shorts, do not ground any of the control module circuits unless instructed. When testing for opens or shorts, do
not apply voltage to any of the control module circuits unless instructed. Only test these circuits with digital voltmeter J 39200, while the control
module connectors remain connected to the control module.
Aftermarket (Add-On) Electrical And Vacuum Equipment
The Aftermarket (Add-On) Electrical and Vacuum Equipment is defined as any equipment installed on a vehicle after leaving the factory that
connects to the electrical or vacuum systems of the vehicle. No allowances have been made in the vehicle design for this type of equipment.
NOTICE: Do not attach add-on vacuum operated equipment to this vehicle. The use of add-on vacuum equipment may result in damage to
vehicle components or systems.
NOTICE: Connect any add-on electrically operated equipment to the vehicle's electrical system at the battery (power and ground) in order to
prevent damage to the vehicle.
The Add-On electrical equipment, even when installed to these strict guidelines, may still cause the Powertrain system to malfunction. This may
also include any equipment which is not connected to the electrical system of the vehicle such as portable telephones and radios. Therefore, the
first step in diagnosing any Powertrain problem is to eliminate all of the Aftermarket electrical equipment from the vehicle. After this is done, if
the problem still exists, diagnose the problem in the normal manner.
Electrostatic Discharge Damage
NOTICE: In order to prevent possible Electrostatic Discharge damage to the PCM, Do Not touch the connector pins or the soldered components on the
circuit board.
The electronic components used in the control systems are often designed in order to carry very low voltage. The electronic components are
susceptible to damage caused by electrostatic discharge. Less than 100 volts of static electricity can cause damage to some electronic components.
There are several ways for a person to become statically charged. The most common methods of charging are by friction and by induction. An
example of charging by friction is a person sliding across a car seat. Charging by induction occurs when a person with well insulated shoes stands
near a highly charged object and momentarily touches ground. Charges of the same polarity are drained off, leaving the person highly charged
with the opposite polarity. Static charges can cause damage Use care when handling and testing the electronic components.
Engine Controls Information
The driveability and emissions information describes the function and operation of the control module. The emphasis is placed on the diagnosis
and repair of problems related to the system.
Engine Components, Wiring Diagrams, and Diagnostic Tables (DTCs):
