ELECTROSTATIC DISCHARGE DAMAGE TO ECM (INFO.TO PREVENT)

Model and Year: 1981-1988 PASSENGER AND LIGHT DUTY TRUCKS WITH AN ELECTRONIC CONTROL MODULE (ECM)

Please add the following information to 6E Section "A" Diagnostic Charts/Trouble Codes, and to Section "C1" Electronic Control Module and Sensors.

NOTICE: To prevent possible Electrostatic Discharge damage: - Do Not touch the ECM connector pins or soldered components on the ECM circuit board. - When handling a PROM, CAL-PAK or Mem-Cal, Do Not touch the component leads, and Do Not remove integrated circuit from carrier.

Electronic components used in control systems are often designed to carry very low voltage, and are very susceptible to damage caused by electrostatic discharge. It is possible for less than 100 volts of static electricity to cause damage to some electronic components. By comparison, it takes as much as 4,000 volts for a person to even feel the zap of a static discharge.

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, in which a charge of as much as 25,000 volts can build up. 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 of either type can cause damage, therefore, it is important to use care when handling and testing electronic components.

General Motors bulletins are intended for use by professional technicians, not a "do-it-yourselfer". They are written to inform those technicians of conditions that may occur on some vehicles, or to provide information that could assist in the proper service of a vehicle. Properly trained technicians have the equipment, tools, safety instructions and know-how to do a job properly and safely. If a condition is described, do not assume that the bulletin applies to your vehicle, or that your vehicle will have that condition. See a General Motors dealer servicing your brand of General Motors vehicle for information on whether your vehicle may benefit from the information.