SER. MAN. UPDATE MESSAGE RESET 'OIL LIFE INDEX' INSTRUCTIONS

SUBJECT: SMU/OWNERS MANUAL UPDATE - "CHANGE OIL NOW" MESSAGE RESET INSTRUCTIONS AND ENTERING SELF- DIAGNOSTICS PROCEDURE

VEHICLES AFFECTED: 1991-92 C, H MODELS

1991-92 Eighty-Eight and Ninety-Eight "Oil Life Index" reset instructions:

To reset the "CHANGE OIL NOW" message displayed on the DIC:

- Press and release the "Test" button. This will acknowledge any existing warning (i.e. change oil now).

- Press and release the "Oil Index" button. Press the "Reset" button and hold for at least five seconds.

This information updates the 1991 Ninety-Eight Owners Manual page 105 and Service Manual page 9H-3 under the heading CHANGE OIL NOW. The 1992 Eighty Eight and Ninety Eight Owner's Manual incorrectly states that the "Test or Reset" button may also be pushed to acknowledge the "CHANGE OIL NOW" message. The "Test" button is the only button that can be pushed to acknowledge the "CHANGE OIL NOW" message.

The 1992 Eighty Eight and Ninety Eight Service Manuals, page 9H-3 under the heading "Oil Change Reminder" incorrectly states that the "Reset" button should be pushed to acknowledge the "CHANGE OIL NOW" message. Change the word "Reset" to "Test".

The procedure in Section OB of the 1992 Eighty Eight and Ninety Eight Service Manuals under the heading of "Resetting Oil Life Index" is also incorrect. Replace this procedure with the procedure listed above.

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Entering Self-Diagnostics Procedure:

- PRESS: "Reset" or "Test" This will acknowledge any existing warnings. - PRESS: "Test" (7) - PRESS: "Reset" - ENTER: 8192 - PRESS: "Enter/Off"

Use this procedure to update the 1992 Ninety-Eight and Eighty-Eight Service Manuals, page 9H-4, under the heading "Self-Diagnostics".

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.