PCM SNAPSHOT IRREGULARITY (DIAGNOSTIC BULLETIN)

SUBJECT: PCM SNAPSHOT ANOMALY (DIAGNOSTIC BULLETIN)

VEHICLES AFFECTED: 1993 "V" MODEL

CONDITION:

Some 1993 Cadillac Allantes may not properly display PCM code snap data due to software anomaly in the diagnostic snapshot code display sequence.

The following sequence of events must occur:

1. After entering diagnostics, all stored codes must be allowed to display.

2. Select HI when "PCM?" is displayed.

3. Select HI when "PCM SNAPSHOT" is displayed.

At this point "POOO SNAPSHOT?" may be displayed and other PCM code snapshots may not appear after "PCM SNAPSHOT?" is selected. Although this is not a correct display, it does not affect the accuracy of the on-board diagnostics.

To enable display of all PCM code snapshots and prevent "POOO SNAPSHOT?" from being displayed, terminate the display of all stored codes after entering diagnostics by pressing LO.

IMPORTANT: DO NOT attempt to repair this condition. Replacement of the BCM, PCM, EPROM'S, or EEPROM's will not correct this condition.

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.