POOR PERFORMANCE DIAGNOSTIC 96 DISPLAYED

POOR PERFORMANCE IN DIAGNOSTIC MODE - 1982 DFI

Poor performance may occur in the diagnostic mode whenever a parameter value of "96" is being displayed on 1982 DFI-equipped vehicles. The normal operating mode is unaffected. This condition is most likely to be encountered while displaying barometric pressure (.0.3), coolant temperature (.0.4), or MAT temperature (.0.5). If a reading of 96 kPa or 96 DEG C is encountered, the system outputs will remain unchanged regardless of sensor values until "96" no longer appears on the display.

Normal calculation of DFI system outputs is bypassed whenever the diagnostic display contains the mode number "9.6" due to the diagnostic system's "output cycling" program. The ECM's cannot distinguish between "9.6" and "96" on the displays.

Diagnostic codes which are set when the ECM recognizes an improper sensor value are set only in the normal operating mode and are not set while in the diagnostic mode. Likewise, "fail-soft" sensor values that are normally substituted to maintain vehicle operation when a code is set are not substituted in the diagnostic mode. Should an intermittent vehicle condition occur while in diagnostic mode, the service technician will not have all the diagnostic benefits normally provided by the DFI system. Therefore, while the parameter display can be very useful to technicians diagnosing specific conditions, customers who are aware of the diagnostic mode should be discouraged from operating the vehicle in this mode.

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.