Due to revisions in the affected model years, with the addition of 1995 Saturns, this bulletin supersedes bulletin 92-T-47A, which should be discarded.
CONDITION: A serial communication interface (SCI) failure causing no powertrain control module (PCM) communication with portable diagnostic tool (PDT) and Service Stall System (SSS). With a SCI failure, the PDT or SSS cannot establish communication with the PCM, however, the vehicle's operation is normal.
CAUSE: In order for the PDT to communicate with the PCM, the PCM must issue a polling message. During certain communication modes, the PCM does not receive all of the information required to issue the poll message and will continue to wait for further data, causing a communication problem.
CORRECTION: Turn the ignition off, wait 10 seconds to reset the PCM and then start the vehicle.
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.