INFO ON OPERATING CHAR OF CJ2 AUTOMATIC CLIM. CONTROL. Buick LeSabre 1998

THIS IS A MONTHLY SERVICE NEWSLETTER ARTICLE. THIS IS NOT INTENDED TO BE A PUBLISHED BULLETIN.

SUBJECT: INFORMATION ON OPERATING CHARACTERISTICS OF CJ2 AUTOMATIC CLIMATE CONTROL

MODELS: 1994-98 BUICK LESABRE WITH CJ2 CLIMATE CONTROL

MISUNDERSTOOD PRODUCT PERFORMANCE CHARACTERISTICS ON THE CURRENT LESABRE COULD LEAD TO A CUSTOMER COMPLAINT AND DIFFICULTY IN DIAGNOSING.

THE AUTOMATIC HVAC CONTROL SYSTEM BEGINNING WITH THE 1994 BUICK LESABRE INCLUDES AN IDLE RECIRCULATION FEATURE WHICH IS USED TO PROVIDE ADDITIONAL COOLING BY SHIFTING TO RECIRC A/C MODE WHEN THERE IS LIMITED COOLING CAPACITY IN THE VEHICLE. THIS WILL ONLY OCCUR WHEN THE VEHICLE IS AT IDLE, IN HOT AMBIENT ENVIRONMENTS AND WHEN ALL THE FOLLOWING CRITERIA ARE MET:

- IGNITION ON TIME IS GREATER THAN 102.4 SECONDS - VEHICLE SPEED IS LESS THAN 10 MPH FOR MORE THAN 56 SECONDS - HVAC PROGRAM NUMBER IS LESS THAN 80 - DISPLAYED OUTSIDE TEMPERATURE IS GREATER THAN 90 DEGREES F - OAT SENSOR A/D COUNTS FALLING

ONCE THESE CONDITIONS ARE MET, THE SYSTEM WILL AUTOMATICALLY CHANGE TO THE RECIRC A/C MODE AND REMAIN IN IDLE RECIRC UNTIL ONE OF THE FOLLOWING IS MET:

- VEHICLE SPEED EXCEEDS 30 MPH - HVAC PROGRAM NUMBER IS GREATER THAN 90 - OAT SENSOR A/D COUNTS RISING

MANUALLY SELECTING ANOTHER MODE OR CHANGING THE SET TEMPERATURE WILL NOT EXIT IDLE RECIRC UNLESS IT RESULTS IN A PROGRAM NUMBER GREATER THAN 90.

CUSTOMERS WHO HAVE SELECTED AUTO OR HAVE MANUALLY SELECTED AN A/C MODE WILL NOT NOTICE A SIGNIFICANT CHANGE WHEN THE IDLE RECIRC ROUTINE IS ENTERED. HOWEVER, IF A CUSTOMER HAS SELECTED A MODE OTHER THAN A/C, THE IDLE RECIRC ROUTINE WHEN ENTERED WILL ABRUPTLY CHANGE THE MODE TO A/C. THIS ABRUPT CHANGE IN MODE MAY BE PERCEIVED AS A FAULT IN THE HVAC SYSTEM. THIS IS NOT A FAULT, BUT A NORMAL RESPONSE OF THE UNIT. AN EXAMPLE OF THIS WOULD BE IF THE CUSTOMER WAS MANUALLY SELECTING A MODE OTHER THAN A/C AND SETTING THE TEMPERATURE CONTROL TO THE COLDEST SETTING (60 DEGREES F).

FIELD INCIDENTS ARE LOW, HOWEVER THIS WILL CONTINUE TO BE MONITORED FOR ADDITIONAL COMPLAINTS. IF CUSTOMER ASSISTANCE IS SOUGHT FOR THIS CONDITION, REPLACEMENT PROGRAMMERS (PROHIBITING IDLE RECIRC FROM BEING ENTERED WHEN THE MODE HAS BEEN MANUALLY SELECTED) ARE AVAILABLE ON A LIMITED BASIS THROUGH TECHNICAL ASSISTANCE.

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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.