A/C - Reverts to Econ Mode, Compressor Inop. and Code 48

Bulletin Number: 93-1-7
Reference Number: 201203
Publish Date: 10/92

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

Models Affected:
1993 SSE MODELS W/C68

MODELS AFFECTED:

1993 SSE with C68 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.