Vehicle Damage Warnings

ELECTRICAL
^ Fully release connector locks prior to disconnecting.
^ Be sure connector insulators and shields are in place and connectors are fully seated.
^ Never connect or disconnect electrical connections with the ignition switch in the "ON" position unless specifically directed to do so in a test procedure.
^ Never use a self powered test lamp to check continuity.
^ Avoid arcing or shorting when working on or testing circuits.
^ Do not probe wires through insulation, damage to the insulation can lead to corrosion of the wire causing system failure.

DIGITAL VOLT/OHM METER
Use a Digital Volt-Ohm Meter (DVOM) with a minimum 10 mega-ohms internal impedance when testing an Powertrain Control Modules (PCM) or related component, unless use of an analog meter is specified by a test procedure.

Analog meters have low internal impedance and will "load" low voltage circuits, resulting in inaccurate measurements and possible damage to components.


TESTING PROCEDURES
Always follow recommended testing procedures. Never ground or apply voltage to a circuit unless specified by a testing procedure. PCM provide a regulated constant low voltage source to some circuits, which may require a minimum resistance (impedance) to operate. Directly grounding or applying battery power to these circuits could damage the PCM and cause a system failure.

ELECTROSTATIC DISCHARGE
Electronic components used in automotive computers are designed to operate at very low voltages (3-5V), and are extremely susceptible to damage caused by static electrical discharge. Voltages as low as 12 volts can damage computer circuits. By comparison, it takes as much as 4,000 volts of static discharge for a person to even feel the "ZAP," and there is no way of knowing whether the charge is positive or negative in nature.

There are several ways in which a person can become statically charged. The most common methods of charging are by friction and induction.

Charging By Friction
Friction between organic materials (such as cotton or leather) and synthetics (such as plastic, vinyl, or glass) will generate static charges as great as 25,000 volts. This can happen by simply sliding across a car seat or by wearing a cotton shirt under a coat made of synthetic materials.

Charging By Induction
Charging by induction occurs when a person standing near a highly charged object (strong magnetic field such as a transformer) momentarily touches ground. Like charges are displaced to ground, leaving the person highly charged with opposite polarity.

Precautions
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.

Discharge any static electricity before handling sensitive parts by touching ground or maintaining a ground connection to a bare skin area like the wrist. DO NOT touch these components without the use of wrists ground straps which have a minimum resistance of 1 Megohm.