CLOCK KEEPS INACCURATE TIME POSSIBLE BCM CIRCUITRY. Buick Riviera 1989

VEHICLES AFFECTED: 1986-89 E/K

This bulletin has been revised to add additional symptom description to the title and first paragraph.

Clocks on some 1986-1989 Eldorados and Sevilles, and 1989 Rivieras and Reattas, and 1989 Toronados with Visual Information Center (VIC) may gain or lose time or experience reset of date and time intermittently. The amount of time may vary from a few minutes to several hours.

IMPORTANT: A normally operating clock may lose or gain up to two minutes per month. To repair this condition check the PROM I.D. and install the appropriate new PROM using the following procedure:

1988-1989 Eldorados and Sevilles:

1. Determine the amount of time gained or lost. If it is less than two minutes over a one-month period, the clock is operating properly.

2. Determine whether the trip odometer or climate control setting is affected, or if a BCM code B552 is set. If so, refer to the Service Information Manual for BCM power and ground diagnosis.

3. Check PROM I.D. (BD99). Refer to Section 8D of the Service Information Manual.

4. If the PROM I.D. is: 1988 - 0186 or 8256 1989 - 3776 or 3426 Replace the EPROM with: 1988 - P/N 16139065 PROM I.D. 9066 1989 - P/N 16138881 PROM I.D. 8766

5. If the PROM I.D. is not: 1988 - 0186 or 8256 1989 - 3776 or 3426 Refer to the Service Information Manual for BCM power and ground diagnosis.

1986-1987 Eldorados and Sevilles:

1. Determine the amount of time gained or lost. If it is less than two minutes over a one-month period, the clock is operating properly.

2. Determine whether the trip odometer or climate control setting is affected, or if a BCM code B552 is set. If so, refer to the Service Information Manual for BCM power and ground diagnosis.

3. If the grounds are clean and tight and the clock's accuracy is still not within specifications, determine the degree of time gain or loss. If the clock is losing or gaining a few minutes per week or month, replace the BCM. The yellow return tag provided with the replacement BCM should be included when the BCM is returned for the core charge. The yellow tag must include a detailed explanation of the condition, the degree to which the clock is inaccurate, and the time standard used (e.g., telephone time).

If the clock is losing or gaining hours at a time, check the BCM PROM I.D., parameter BD99. For 1986 Eldorados and Sevilles, it should be 0206. For 1987 Eldorados and Sevilles, it should be 0216. If the PROM I.D. is not correct, replace the BCM EPROM with part numbers listed below:

Model BCM PROM Year Part Number ---- -----------

1986 16140207 1987 16140210

1989 Rivieras, Reattas, and Toronados:

1. Determine the amount of time gained or lost. If it is less than two minutes over a one-month period, the clock is operating properly.

2. Determine whether the trip odometer or climate control setting is affected, or if a BCM code B552 is set. If so, refer to the Service Information Manual for BCM power and ground diagnosis.

3. Check PROM I.D. (BD99). Refer to Section 8D of the Service Information Manual.

Rivieras and Reattas:

4. If the PROM I.D. is: 3424, 3764, or 0574

Replace the EPROM with: P/N 16138872

5. If the PROM I.D. is not: 3424, 3764, or 0574

Refer to the Service Information Manual for BCM power and ground diagnosis.

Toronados (with VIC):

4. If the PROM I.D. is: 3423, 3763, or 0583

Replace the EPROM with: P/N 16138867

5. If the PROM I.D. is not: 3423, 3763, or 0583

Refer to the Service Information Manual for BCM power and ground diagnosis.

All parts are currently available from CANSPO.

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.