OIL LIFE MONITOR (NEW P/N) ERRATIC MESSAGE - CHANGE OIL

SUBJECT: OIL LIFE MONITOR (NEW SERVICE PART)

MODELS AFFECTED: 1991 PARK AVENUE/PARK AVENUE ULTRA

THIS BULLETIN IS BEING REVISED TO CHANGE PARTS AVAILABILITY, ADD INFORMATION TO THE CORRECTION SECTION, AND TO INCLUDE WARRANTY INFORMATION.

CONDITION:

----------- Some 1991 Park Avenue/Park Avenue Ultras with option "UB3" Instrumentation (includes Engine Oil Life), may exhibit a condition where the customer complains that the "Change Oil Soon" telltale is illuminated whenever the ignition is on. In some cases it may stay on only for one ignition cycle and go out the next time the key is turned on.

CAUSE:

------- The cause of this condition may be one of three problems:

1. With the ignition on, engine off and the module has determined that it is time for the oil to be changed, a false code 27 can be set in the module and the "Change Oil Soon" telltale will stay illuminated. This code will clear (show up as history only) when the engine is started and will clear when the module is reset.

2. With the ignition on, engine running or not, the module goes into a data scramble which causes a code 14 to be stored and the "Change Oil Soon" telltale will stay illuminated. This code will clear when the module is reset but the condition could reoccur.

3. With the ignition on, engine running or not, the module can falsely set a code 13 indicating loss of data from the ECM. The "Change Oil Soon" telltale will stay illuminated and this code will clear when the module is reset. This condition is intermittent and may correct itself, turning the "Change Oil Soon" telltale off during an ignition cycle causing intermittent warning light operation.

CORRECTION:

----------- To correct the above conditions, a new Engine Oil Life Module has been released for service.

Part Number 25606364 is expected to be available on December 2, 1991. In case of limited inventory, parts will be placed on 400 control to waive VIP surcharges. Only verifiable emergency VIP orders will be accepted. SPO will make every effort to obtain parts. However, the part will be shipped premium transportation at dealer's expense and all other order types will be placed on backorder until the 400 control is removed.

After replacing the module, the engine oil and filter should also be changed to provide a baseline for the oil life monitor.

WARRANTY INFORMATION:

Labor Operation No.: T5252 Labor Time: .6 hr. to replace the module Other Labor Hrs. (OLH) .4 hr. to change the oil and filter Failed Part Number 25606364

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.