CODE B446, B447 & B448 DIAG. REPLACE WITH REVISED PROM

HEATING AND AIR CONDITIONING

SUBJECT: B446, B447, AND B448 CODE DIAGNOSIS (REPLACE PROM)

VEHICLES AFFECTED: 1986-90 E, K

Some 1986-1990 Eldorados and Sevilles may experience low ref rigerant codes, showing a code B446, codes B446 and B447, or code B448. To diagnose and repair these conditions follow the appropriate trouble tree in Figure 1, Figure 2 and/or Figure 3.

On 1988-1990 vehicles a premature low ref rigerant code B446/B447 may be displayed in cool ambient temperatures (45F- 60F). This condition can be repaired by following the trouble tree (Figure 1) for diagnosis and, if necessary, replacing the PROM in accordance with the chart below:

PROM-CHART

ORIGINAL PROM I.D. NEW PROM I.D.

Broadcast PROM Broadcast Code I.D. Code I.D. P/N

1988 AJUT 0186 AUPL 1996 16151993 ANUD 8256 ASCD 9066

1989 ANDP 3776 AUKN 1046 16151037 APYK 3426 ASAP 8766 ATPU 5916

1990 ANXX 9236 AUKP 1056 16151314

NOTE: Failure to recover, evacuate, and recharge with the proper amount of refrigerant may result in recurrence of low refrigerant indicator.

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.