TROUBLESHOOTING
U–77
U
Diagnostic procedure
STEP INSPECTION ACTION
1 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.
No Go to next step.
2 INSPECT A/C COMPRESSOR SLIPPAGE
NOISE
• Is there a squeaking or whirling sound (A/C
compressor slippage noise)?
Yes Go to Step 14.
No Go to next step.
3 INSPECT A/C COMPRESSOR
INTERFERENCE NOISE
• Is there a rattling or vibrating sound
(interference noise)?
Yes Go to Step 18.
No Go to next step.
4 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)
No Condition is normal. (Recheck malfunction symptoms.)
5 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.
No Condition is normal. (Noise occurs for 2—3 seconds
immediately after A/C compressor turns on.)
6 INSPECT IDLE SPEED
• Inspect idle speed.
(See F–8 IDLE SPEED INSPECTION)
• Is it okay?
Yes Go to next step.
No Follow the repair instruction described in section F, then go
to Step 19.
7 INSPECT REFRIGERANT AMOUNT
• Inspect refrigerant amount.
• Is it okay?
Yes Go to Step 10.
No Go to next step.
8 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.
No 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.
9 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.
No 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.
10 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.
No Troubleshooting completed.
Explain repair to customer.
11 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.
No Replace A/C compressor, then go to Step 19.
12 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.
No Go to next step.