REPEAT ACP CODE A047 OR 1347. Cadillac Eldorado 1995

REVISON: 12/03/96

THIS BULLETIN IS BEING REVISED TO INCLUDE CODE 1347 AND ADD 1996 AND 1997 MODEL YEARS. PLEASE DISCARD CORPORATE BULLETIN NUMBER 53-12-06 (SECTION 1 - HVAC). ----------------------------------------------------------------------

SUBJECT: INFORMATION ON REPEAT ACP CODE A047 OR 1347

MODELS: 1994-97 CADILLAC CONCOURS, DEVILLE, ELDORADO, SEVILLE WITH 4.9L OR 4.6L ENGINE (VINS B, Y, 9 - RPOS L26, LD8, L37)

EXCESSIVE ACR4 CHARGING STATION REFRIGERANT TANK PRESSURE MAY CAUSE REPEAT ACP CODE A047 OR 1347.

EXCESSIVE REFRIGERANT TANK PRESSURE MAY BE AN INDICATOR THAT A TANK CONTAINS EXCESSIVE NON-CONDENSABLE GAS (REFERRED TO AS NCG). THIS CONTAMINANT IS USUALLY AIR. AIR IS MOST LIKELY INTRODUCED INTO AN A/C SYSTEM BY AN IMPROPER SERVICE PROCEDURE. HOWEVER, IN SOME INSTANCES, THE CHARGING STATION MAY BE AT FAULT.

THE CORRECTIVE ACTION IS BROKEN DOWN INTO TWO REPAIRS:

1. EXCESSIVE CHARGING STATION TANK PRESSURE.

2. REPEAT ACP CODE A047 OR 1347.

REPAIR 1 - EXCESSIVE CHARGING STATION TANK PRESSURE:

1. MAKE CERTAIN THAT THE ACR4 EQUIPMENT HAS NOT BEEN USED FOR AT LEAST 12 HOURS. IT IS RECOMMENDED THAT THE EQUIPMENT BE LEFT IN AN AREA WHERE THE TEMPERATURE WILL REMAIN CONSTANT OVERNIGHT TO ALLOW THE TEMPERATURE OF THE REFRIGERANT IN THE TANK TO STABILIZE.

2. RECORD THE SURROUNDING AIR TEMPERATURE NEXT TO THE ACR4 REFRIGERANT TANK.

IMPORTANT: A MAJOR ASSUMPTION IS THAT THE AMBIENT AIR TEMPERATURE NEXT TO THE TANK REPRESENTS THE REFRIGERANT TEMPERATURE IN THE TANK. FAILURE TO TAKE CARE IN MEASURING THE TEMPERATURE COULD RESULT IN UNNECESSARY WORK.

3. CLOSE BOTH LIQUID (BLUE) AND VAPOR (RED) VALVES ON THE ACR4 TANK.

4. DISCONNECT LOW SIDE (BLUE) SERVICE HOSE FROM THE BACK OF THE ACR4.

5. SLOWLY DISCONNECT THE TANK VAPOR HOSE (RED) FROM THE BACK OF THE ACR4 AND CONNECT IT TO THE LOW SIDE SERVICE PORT.

6. OPEN THE VAPOR (RED) VALVE ON THE TANK AND RECORD THE TANK PRESSURE ON THE LOW SIDE GAGE.

7. RESTORE HOSES TO THE ORIGINAL POSITION.

8. REFERRING TO THE TABLE BELOW, FIND THE AMBIENT TEMPERATURE MEASURED IN STEP 2. COMPARE THE PRESSURE READING FROM STEP 6 TO THE "MAXIMUM ALLOWABLE PRESSURE". IF THE PRESSURE READING FROM STEP 6 IS LESS THAN THE "MAXIMUM ALLOWABLE PRESSURE", NO FURTHER ACTION IS NECESSARY.

IMPORTANT: THE CLOSER THE TANK PRESSURE IS TO THE DESIRED TANK PRESSURE, THE BETTER THE A/C SYSTEM WILL PERFORM.

9. IF THE PRESSURE READING FROM STEP 6 EXCEEDS THE MAXIMUM ALLOWABLE PRESSURE FROM THE TABLE, OPEN BOTH TANK VALVES AND OPERATE THE ACR4 THROUGH 4 OR 5 EVACUATION CYCLES. THIS WILL ACTIVATE THE AUTOMATIC AIR PURGE TO LOWER THE TANK PRESSURE.

IMPORTANT: STATION SHOULD NOT BE CONNECTED TO VEHICLE.

10. REPEAT THE TANK PRESSURE CHECKING PROCEDURE THE NEXT DAY TO DETERMINE IF THE PRESSURE HAS BEEN REDUCED TO ACCEPTABLE LEVELS. IF THE TANK PRESSURE HAS BEEN REDUCED BUT IS NOT ACCEPTABLE, CYCLE WITH ACR4 THROUGH MORE EVACUATION CYCLES AND RECHECK THE NEXT DAY. CONTINUE PROCESS UNTIL ACCEPTABLE PRESSURE IS OBTAINED. IF THE TANK PRESSURE IS NOT REDUCED THROUGH THE EVACUATION CYCLING, THEN KENT-MOORE SHOULD BE CONTACTED AT 1-800-345-2233.

AMBIENT DESIRED TANK MAXIMUM ALLOWABLE TEMPERATURE PRESSURE PRESSURE =========== ============ =================

15.5 DEGREES CELSIUS 393 KPA (57 PSI) 476 KPA (69 PSI) (60 DEGREES FAHRENHEIT)

18.3 DEGREES CELSIUS 441 KPA (64 PSI) 531 KPA (77 PSI) (65 DEGREES FAHRENHEIT)

21.1 DEGREES CELSIUS 490 KPA (71 PSI) 593 KPA (86 PSI) (70 DEGREES FAHRENHEIT)

23.8 DEGREES CELSIUS 538 KPA (78 PSI) 662 KPA (96 PSI) (75 DEGREES FAHRENHEIT)

26.6 DEGREES CELSIUS 593 KPA (86 PSI) 724 KPA (105 PSI) (80 DEGREES FAHRENHEIT)

29.4 DEGREES CELSIUS 655 KPA (95 PSI) 800 KPA (116 PSI) (85 DEGREES FAHRENHEIT)

32.2 DEGREES CELSIUS 717 KPA (104 PSI) 876 KPA (127 PSI) (90 DEGREES FAHRENHEIT)

35 DEGREES CELSIUS 786 KPA (114 PSI) 958 KPA (139 PSI) (95 DEGREES FAHRENHEIT)

37.7 DEGREES CELSIUS 855 KPA (124 PSI) 1048 KPA (152 PSI) (100 DEGREES FAHRENHEIT)

REPAIR 2 - REPEAT ACP CODE A047 OR 1347:

EXCESSIVE NCG MAY BE INADVERTENTLY FORCED INTO A VEHICLE DURING A SERVICE PROCEDURE. THIS SERVICE PROCEDURE COULD HAVE BEEN NECESSITATED AS THE RESULT OF A "LEGITIMATE" CODE A047 OR 1347. FOR EXAMPLE, A SYSTEM LEAK CAUSED BY A DEFECTIVE "O" RING. THE EXCESSIVE NCG MAY CAUSE A REPEAT CODE A047 OR 1347 TO SET. WHEN USING SNAPSHOT DATA TO DIAGNOSE THESE CODES, VALUES OF -40 TO 0 SHOULD BE DISREGARDED.

A CODE A047 OR 1347 SHOULD ALWAYS BE TESTED AND SERVICED AS A LOW REFRIGERANT LEVEL CONDITION; HOWEVER, IF NO LEAK OR OTHER CAUSE CANNOT BE FOUND, EXCESSIVE NCG MAY BE AT FAULT.

CORRECT A HIGH PRESSURE CONDITION IN THE ACR4 TANK PRIOR TO SERVICING A VEHICLE'S AIR CONDITION SYSTEM. THE VEHICLE'S AIR CONDITION SYSTEM SHOULD BE EVACUATED FOR A MINIMUM OF 20 MINUTES BEFORE RECHARGING. THE EVACUATION MODE OF THE ACR4 IS THE PROCESS WHICH NCG IS PURGED FROM THE SYSTEM.

FIGURES: 0 ATTACHMENTS: 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.