Mazda 6 2002 Workshop Manual page 1165

NO.8 NO COOL AIR
End Of Sie
8 No cool air
DESCRIPTION • Magnetic clutch does not operate.
• Malfunction in PCM A/C cut control system (Step 3)
• Malfunction in climate control unit (Step 4)
• Malfunction in refrigerant pressure switch (Steps 5, 7—9)
POSSIBLE • Malfunction in PCM (A/C signal) (Step 6)
CAUSE • Malfunction in PCM (IG1 signal) (Steps 10, 11)
• Malfunction in A/C compressor (Step 12)
• Malfunction in A/C relay (Steps 13—15)
• Malfunction in evaporator temperature sensor (Step 16)
• When performing an asterisked (*) troubleshooting inspection, shake the wiring harness and connectors while
performing the inspection to discover whether poor contact points are the cause of any intermittent
malfunctions. If there is a problem, check to make sure connectors, terminals and wiring harnesses are
connected correctly and undamaged.
Diagnostic procedure
STEP
1 INSPECT AIR BLOW OUT
• Does air blow out?
2 INSPECT A/C COMPRESSOR OPERATION
• Start engine.
• Turn A/C switch and fan switch on.
• Does A/C compressor operate?
3 INSPECT FOR DTC IN PCM
• Inspect for DTCs related to the PCM on-
board diagnostic system.
• Are any DTCs displayed?
4 INSPECT TO SEE WHETHER MALFUNCTION
IS IN CLIMATE CONTROL UNIT OR
ELSEWHERE
• Does cool air blow out when terminal 1P of
climate control unit connector (24-pin, A/C
signal) is grounded?
5* INSPECT TO SEE WHETHER MALFUNCTION
IS IN A/C SIGNAL CIRCUIT (BETWEEN
REFRIGERANT PRESSURE SWITCH AND
PCM) OR ELSEWHERE
• Test voltage at following terminal of
refrigerant pressure switch.
— Terminal B (A/C signal)
• Is voltage approimately 12 V?
6* INSPECT TO SEE WHETHER MALFUNCTION
(LACK OF CONTINUITY) IS IN WIRING
HARNESS (BETWEEN REFRIGERANT
PRESSURE SWITCH AND PCM) OR PCM
• Test voltage at A/C signal terminal of PCM.
• Is voltage approimately 12 V?
7 INSPECT TO SEE WHETHER MALFUNCTION
IS IN REFRIGERANT PRESSURE SWITCH,
REFRIGERANT AMOUNT, OR ELSEWHERE
• Does cool air blow out when terminals A and
B of refrigerant pressure switch connector
are shorted?
8* INSPECT TO SEE WHETHER MALFUNCTION
IS IN WIRING HARNESS (BETWEEN
REFRIGERANT PRESSURE SWITCH AND
CLIMATE CONTROL UNIT) OR ELSEWHERE
• Test voltage at following terminal of climate
control unit.
— Terminal 1P (24-pin, A/C signal)
• Is voltage approimately 12 V?
TROUBLESHOOTING
INSPECTION
Yes Go to net step.
No Go to Step 1 of troubleshooting indees No.1 and 2.
Yes Go to Step 1 of troubleshooting inde No.7.
No Go to net step.
Yes Go to appropriate inspection procedure.
No Go to net step.
Yes Replace climate control unit, then go to Step 17.
No Release short, then go to net step.
Yes Go to Step 7.
No Go to net step.
Yes Repair wiring harness between PCM and refrigerant
pressure switch, then go to Step 17.
No Inspect PCM, then go to Step 17.
Yes Go to Step 9.
No Go to net step.
Yes Go to Step 10.
No Repair wiring harness between refrigerant pressure switch
and climate control unit, then go to Step 17.
A6E858001038W10
ACTION
U–75
U