POOR A/C PERFORMANCE (DIAG. PROCESS, REPL. A/C COMPRESSOR). Pontiac Firebird 1993

SUBJECT: POOR A/C PERFORMANCE (DIAGNOSTIC PROCESS, REPLACE A/C COMPRESSOR LOW PRESSURE CUT OFF SWITCH)

MODELS: 1993 CHEVROLET CAMARO 1993 PONTIAC FIREBIRD

CONDITION:

SOME CUSTOMERS MAY COMMENT ABOUT INADEQUATE A/C PERFORMANCE OR INTERMITTENT A/C OPERATION WHICH MAY BE ACCOMPANIED BY RAPID CYCLING OF A/C COMPRESSOR.

CAUSE:

FAULTY COMPONENTS OR LOW REFRIGERANT CHARGE MAY CAUSE COMMENTS OF POOR A/C PERFORMANCE OR INTERMITTENT A/C COMPRESSOR SYSTEM OPERATION.

CORRECTION:

1. ALL A/C SYSTEM PERFORMANCE COMMENTS SHOULD BE DIAGNOSED UTILIZING SERVICE MANUAL 1B1-10, "INSUFFICIENT COOLING CHECK" INCLUDING INITIAL CHECK OF ECM ON BOARD DIAGNOSTIC SYSTEM PER SERVICE MANUAL SECTION 6E3. THE VEHICLE ECM DOES CONTAIN DIAGNOSTIC CODES FOR ANALYSIS OF FAULTY A/C SYSTEM COMPONENTS AND LOW REFRIGERANT CHARGE. THE ECM ON BOARD DIAGNOSTIC SYSTEM MAY ALSO INTERMITTENTLY DISABLE THE A/C COMPRESSOR AS DESCRIBED IN SERVICE MANUAL SECTION 6E3.

2. IF A POTENTIAL REFRIGERANT LEAK IS INDICATED BY THE ON BOARD DIAGNOSTIC SYSTEM OR A/C PERFORMANCE TEST, CONDUCT LEAK TESTING ACCORDING TO THE PROCEDURE DESCRIBED IN THE SERVICE MANUAL SECTION 1B-5. FIGURE 1 IN SECTION 1B-5 ILLUSTRATES ALL A/C JOINTS. LEAK TESTING MUST BE DONE AT ALL A/C JOINTS (INCLUDING SENSOR/SWITCH JOINTS).

3. IF A REFRIGERANT LEAK IS FOUND AT THE A/C COMPRESSOR LOW PRESSURE CUT OFF SWITCH BASE, THE SWITCH MAY HAVE BEEN CRACKED DUE TO OVER TORQUING. IF NECESSARY, REPLACE THE A/C COMPRESSOR LOW PRESSURE CUT OFF SWITCH WITH NEW P/N 10242579. DO NOT EXCEED NEW TORQUE SPECIFICATION OF 3 N.M (26.5 LB.IN.). CURRENT SERVICE MANUAL SPECIFICATION OF 6 N.M IS INCORRECT. THE "O" RING SEAL AND THE FITTING FOR THIS JOINT SHOULD ALSO BE INSPECTED FOR CUTS/NICKS PER SERVICE MANUAL PROCEDURE AND REPLACED IF NECESSARY. LEAK CHECK SHOULD BE REPEATED AFTER RE-ASSEMBLY. FIGURE 1 IN SECTION 1B-5 ILLUSTRATES MOST REFRIGERATION SYSTEM COMPONENTS, INCLUDING THE LOW PRESSURE CUT OFF SWITCH.

4. VEHICLE SHOULD BE ROAD TESTED AFTER DIAGNOSIS AND CORRECTION OF ANY CONDITIONS TO ASSURE PROPER A/C SYSTEM OPERATION. THE ECM A/C PERFORMANCE DIAGNOSTIC CODE (CODE 61) WILL NOT SET AT VEHICLE IDLE; VEHICLE MUST BE OPERATED AT ROAD SPEEDS FOR SEVERAL MINUTES FOR THE ON BOARD DIAGNOSTICS TO FUNCTION.

PART AVAILABILITY:

PARTS ARE CURRENTLY AVAILABLE FROM GMSPO.

WARRANTY INFORMATION:

LABOR OPERATION: T3370 LABOR TIME: 0.6 HR. ADD TO RECOVER AND RECHARGE A/C: 0.7 HR.

FIGURES: 0

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.