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Mazda 6. Manual - part 393

U–76

TROUBLESHOOTING

End Of Sie

NO.9 NOISE WHILE OPERATING A/C SYSTEM

A6E858001038W11

INSPECT TO SEE WHETHER MALFUNCTION
IS IN REFRIGERANT PRESSURE SWITCH OR
REFRIGERANT AMOUNT

• Inspect refrigerant pressure switch.

• Is it okay?

Yes

If refrigerant amount is empty, replace condenser, vaccum
refrigerant line more than 30 minutes by vacuum pump,
and add refrigerant to specified level, then go to Step 17.

Replace refrigerant pressure switch, then go to Step 17.

INSPECT TO SEE WHETHER MALFUNCTION
(LACK OF CONTINUITY) IS IN A/C CONTROL
SIGNAL CIRCUIT (BETWEEN A/C RELAY
AND PCM) OR ELSEWHERE

• Does cool air blow out when terminal E of A/

C relay connector (A/C control signal) is
grounded?

Yes

Release short, then go to next step.

Go to Step 12.

11*

INSPECT TO SEE WHETHER MALFUNCTION
(LACK OF CONTINUITY) IS IN PCM OR
WIRING HARNESS (BETWEEN A/C RELAY
AND PCM)

• Test voltage at the A/C relay control signal

terminal of PCM.

• Is voltage approximately 12 V?

Yes

Inspect PCM, then go to Step 17.

Repair wiring harness between A/C relay and PCM, then go
to Step 17.

12*

INSPECT TO SEE WHETHER MALFUNCTION
IS IN MAGNETIC CLUTCH OR ELSEWHERE

• Test voltage at the following terminal of

magnetic clutch thermal protector.
— Terminal A (magnetic clutch operation

signal)

• Is voltage approximately 12 V?

Yes

Inspect magnetic clutch, then go to Step 17.

Go to next step.

INSPECT FUSE

• Are A/C relay power supply fuses okay?

Yes

Go to next step.

Replace fuse, then go to Step 17. If fuse burns out
immediately, go to next step.

INSPECT WIRING HARNESS BETWEEN
FUSE BLOCK AND A/C RELAY FOR LACK
OF CONTINUITY

• Test voltages at following terminals of A/C

relay.
— Terminal A (A/C relay control signal)
— Terminal C (A/C control signal)

• Are voltages approximately 12 V?

Yes

Go to next step.

Repair wiring harness between fuse block and A/C relay,
then go to Step 17.

INSPECT TO SEE WHETHER MALFUNCTION
IS IN A/C RELAY OR WIRING HARNESS
(BETWEEN A/C RELAY AND MAGNETIC
CLUTCH) AND EVAPORATOR
TEMPERATURE SENSOR

• Test voltage at the following terminal of A/C

relay.
— Terminal D (magnetic clutch operation

signal)

• Is voltage approximately 12 V?

Yes

Inspect wiring harness between A/C relay and magnetic
clutch.

• If above wiring harness is OK, go to next step.

• If above wiring harness malfunctions, repair wiring

harness, then go to Step 17.

Replace A/C relay, then go to Step 17.

INSPECT EVAPORATOR TEMPERATURE
SENSOR

• Inspect evaporator temperature sensor.

• Is it okay?

Yes

Go to next step.

Replace evaporator temperature sensor, then go to next
step.

CONFIRM THAT MALFUNCTION SYMPTOMS
DO NOT RECUR AFTER REPAIR

• Does cool air blow out? (Are the results of

refrigerant system performance test okay?)

Yes

Troubleshooting completed. Explain repairs to customer.

Recheck malfunction symptoms, then repeat from Step 1 if
malfunction recurs.

STEP

INSPECTION

ACTION

Noise while operating A/C system.

DESCRIPTION

• Noise from magnetic clutch, A/C compressor, hose or refrigerant line.

POSSIBLE

CAUSE

• Magnetic clutch operation noise (Step 4)

• A/C compressor vane noise (Steps 5—13)

• A/C compressor slippage noise (Steps 14—17)

• Hose or refrigerant line interference noise (Step 18)

TROUBLESHOOTING

U–77

Diagnostic procedure

STEP

INSPECTION

ACTION

CHECK A/C COMPRESSOR VANE NOISE

• Is there a jingling, popping, beeping, or

buzzing sound (A/C compressor vane
noise)?

Yes

Go to Step 5.

Go to next step.

INSPECT A/C COMPRESSOR SLIPPAGE
NOISE

• Is there a squeaking or whirling sound (A/C

compressor slippage noise)?

Yes

Go to Step 14.

Go to next step.

INSPECT A/C COMPRESSOR
INTERFERENCE NOISE

• Is there a rattling or vibrating sound

(interference noise)?

Yes

Go to Step 18.

Go to next step.

INSPECT MAGNETIC CLUTCH OPERATION
NOISE

• Is there a clicking sound (magnetic clutch

operation noise)?

Yes

Adjust clearance between pressure plate of magnetic clutch
and A/C compressor pulley, then go to Step 19.
(See

U–38 MAGNETIC CLUTCH ADJUSTMENT

)

Condition is normal. (Recheck malfunction symptoms.)

INSPECT A/C COMPRESSOR NOISE TIME

• Is noise heard continuously for more than 3

seconds after A/C compressor comes on?

Yes

Go to next step.

Condition is normal. (Noise occurs for 2—3 seconds
immediately after A/C compressor turns on.)

INSPECT IDLE SPEED

• Inspect idle speed.

(See

F–8 IDLE SPEED INSPECTION

)

• Is it okay?

Yes

Go to next step.

Follow the repair instruction described in section F, then go
to Step 19.

INSPECT REFRIGERANT AMOUNT

• Inspect refrigerant amount.

• Is it okay?

Yes

Go to Step 10.

Go to next step.

INSPECT REFRIGERANT LINES

• Inspect refrigerant lines.

— Is piping free of damage and cracks?
— Are piping connections free of oil grime?

(Visual inspection)

— Are piping connections free of gas

leakage?

— Are piping installation points on

condenser free of gas leakage?

— Are piping installation points on receiver/

drier free of gas leakage?

— Are piping installation points on A/C

compressor free of gas leakage?

— Are piping installation points on A/C unit

free of gas leakage

— Perform gas leak inspection using gas

leak tester.

• Are above items okay?

Yes

Go to next step.

If piping or A/C component(s) is damaged or cracked,
replace then go to Step 19.
If there is gas leakage, repair or replace connection and
replace condenser*, then go to Step 19.

INSPECT EVAPORATOR PIPING
CONNECTIONS IN A/C UNIT FOR GAS
LEAKAGE

• Are piping connections for evaporator in A/C

unit free of gas leakage?

Yes

Adjust refrigerant amount to specified level, then go to Step
19.

If piping is damaged or cracked, replace then go to Step 19.
If there is gas leakage, repair or replace connection and
replace condenser*, then go to Step 19.

CHECK TO SEE WHETHER MALFUNCTION
IS IN COMPRESSOR OIL OR ELSEWHERE

• Add 20 ml {20 cc, 0.8 fl oz} of compressor

oil.

• Is noise heard when racing engine?

Yes

Go to next step.

Troubleshooting completed.
Explain repair to customer.

CHECK TO SEE WHETHER MALFUNCTION
IS IN A/C COMPRESSOR OR ELSEWHERE

• Drain compressor oil.

• Is it contaminated with metal particles?

Yes

Go to next step.

Replace A/C compressor, then go to Step 19.

CHECK TO SEE WHETHER MALFUNCTION
IS SOMEWHERE IN A/C SYSTEM OR
ELSEWHERE

• Is compressor oil whitish and mixed with

water?

Yes

Replace entire A/C system (excluding heater), then go to
Step 19.

Go to next step.

U–78

TROUBLESHOOTING

: If there is gas leakage, air enters into the A/C system. The desiccant within the receiver/drier absorbs the

moisture from the air and becomes saturated. If the A/C system is used in this condition, the inside of the A/C
compressor will begin to rust due to this moisture, which may cause lock up or noise to occur. Therefore,
replacement of the receiver/drier is necessary.

End Of Sie

INSPECT A/C COMPRESSOR OIL

• Is compressor oil darker than normal and

contaminated with aluminum chips?

Yes

Replace A/C compressor and condenser, then go to Step
19. (Since A/C compressor may be worn and receiver/drier
may be clogged, replacement of receiver/drier is
necessary.)

Condition is normal. Recheck malfunction symptoms.

CHECK TO SEE WHETHER MALFUNCTION
IS IN A/C COMPRESSOR OR ELSEWHERE

• Is noise heard immediately after A/C

compressor is stopped?

Yes

Replace A/C compressor, then go to Step 19. (A/C
compressor discharge valve left open)

Go to next step.

INSPECT DRIVE BELT

• Inspect drive belt.

(See

B–3 DRIVE BELT INSPECTION

)