Expo AWD L4-2350cc 2.4L SOHC 16 Valve (1993)
Central Power Supply: Service Precautions
Electrical Precautions
Battery Precautions
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Never use a booster/starter which has a voltage rating above 12 volts to start engine.
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Always ensure the battery is properly connected to the vehicle prior to attempting to start engine.
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Don't disconnect the battery when the engine is running.
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When charging a battery, be sure battery cables are disconnected.
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The battery contains acid and produces explosive gas (hydrogen). Avoid creating sparks near battery.
Electrical Connections and Circuits
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Fully release connector locks prior to disconnecting. Ensure connectors are fully seated and all insulators and shields are in place when
reinstalling.
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Never connect or disconnect electrical connections with the ignition switch in the "ON" position unless specifically directed to do so in a test
procedure.
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Do not use a self powered test lamp to check continuity.
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Do not create any arcing to check the continuity of a circuit.
Electronic Component Handling
STATIC DISCHARGE
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Discharge any static electrical charges before handling electronic parts by touching ground or maintaining a ground connection to a bare skin area
like the wrist.
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Never touch the ECM connector pins, integrated circuit connector pins, or soldered components on the ECM circuit board.
TESTING
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When measuring voltage at the control module harness connector, disconnect harness connector with the ignition OFF, then turn ignition "ON" as
necessary.
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To prevent deforming control module harness connectors, do not probe terminals directly. Instead, insert a pin from the harness side and perform
measurements through pin.
CONTROL UNIT DAMAGE
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Do not try to disassemble the control module.
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Before performing electrical welding (for instance, spot welding), disconnect the battery, climate control, injection, cruise control, ECM and radio.
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If temperatures may exceed 176°F (80°C), (example: infra-red spray booth), remove all ECMs.
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Avoid getting water on any of the Fuel and Engine Control System Components.
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Never apply battery power to a component unless directed to do so in a test procedure.
Electronic Component Replacement
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Before servicing electronic components, disconnect the battery ground.
NOTE: Before removing battery ground, access trouble codes. ECM memory will be erased if ground cable is removed.
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Fuel and Engine Control System wiring should be at least 4 inches away from ignition wires.
Electrostatic Discharge
STATIC DISCHARGE PRECAUTIONS
Discharge static by touching ground or maintaining a ground connection to a bare skin area like the wrist before handling electronic parts.
Never touch electronic control module connector pins, integrated circuit connector pins, or soldered components on circuit boards.
Static charges are gradually equalized by moisture in the air but are retained much longer when humidity is low. Use care when handling and
testing electronic components.
WHY STATIC DISCHARGE IS A PROBLEM
Automotive computer systems are designed to operate at 3 - 5 Volts and are susceptible to damage by voltages as low as 12 volts.
It takes up to 4,000 volts of static discharge for a person to feel the "ZAP".
The most common ways to become statically charged are friction and induction.
