A/C REVERTS TO ECON. MODE COMP INOP/CODE 48 STORED MEM.

SUBJECT: A/C SYSTEM REVERTS TO ECON MODE, COMPRESSOR INOPERATIVE AND CODE 48 IS STORED IN MEMORY (CLEAR CODES)

VEHICLES AFFECTED: 1993 "C AND H" WITH C68 OR CJ2 A/C

APPLICATION:

----------- 1993 C/H Models with C68 OR CJ2 A/C and 3800 Engine (VIN L, RPO L27).

CONDITION:

--------- The A/C system reverts to econ mode, compressor will not operate and a code 48 is stored in the memory of the A/C system.

CAUSE:

----- This condition may be caused by having a scan tool plugged in to the car. When a Tech 1 or other scan tool is plugged into the DCL (ALDL) of one of these vehicles, and the air conditioning is on, a code 48 may be set. The scan tool has an effect on normal communications and can cause the system to incorrectly think that the A/C compressor request signal has been lost. It takes approximately five (5) minutes for this code to set.

CORRECTION:

---------- For a code 48 set as a result of this scan tool interface condition, the only correction required is to clear the code. Awareness of this condition will help to avoid its reoccurrence. If there is any possibility that a code 48 was set due to this scanner interface condition, do not replace any parts or attempt repairs. Clear the code, and operate the A/C system normally to see if the code will reset.

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.