SERVICE GUILD: USE OF IAC DRIVER TOOL INFORMATON

MODELS AFFECTED: 1987-88 CENTURYS WITH 2.8L ENGINE (VIN CODE W), 1988-89 REGAL WITH 2.8L ENGINE (VIN CODE W) 1989-90 REGAL WITH 3.1L ENGINE (VIN CODE T)

This bulletin is to inform technicians when using the Idle Air Control (IAC) Driver Tool Number (22M - Concept Technology) or (J 37027 - Kent Moore) on the 2.8L/3.1L MPFI engines that the Diagnostic Test Terminal must be grounded or Field Service Mode entered if a "Scan Tool" is used.

The grounding procedure is fully explained in the diagnostic charts for Service Manual Sections "6E3-A" (Code 35) and "6E3-C2" (Idle Air Control (IAC) Circuit). However, the grounding procedure must also be followed when using the tool for other uses such as: Idle (RPM) Control, Generator Diagnosis, A/C Recharging, etc.

It should also be noted that whenever the IAC system is disconnected or a battery disconnect is made, the "Idle Learn Procedure" in Section "6E3-C2" of the Service Manual should be followed.

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.