NO.9 NO COOL AIR FROM FRONT/REAR VENTS

id070300901400

9
No cool air from front/rear vents
DESCRIPTION
•  Malfunction in A/C compressor control system
•  Magnetic clutch does not operate when the A/C system is turned ON.
POSSIBLE CAUSE
•  Malfunction in PCM A/C cut control system
•  Malfunction in climate control unit
•  Malfunction in refrigerant pressure switch (PCM connector (2 types))
•  Malfunction in refrigerant pressure sensor (PCM connector (3 types))
•  Malfunction in PCM (A/C signal)
•  Malfunction in PCM (IG1 signal)
•  Malfunction in A/C compressor
•  Malfunction in A/C relay
•  Malfunction in evaporator temperature sensor

•  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

INSPECTION

ACTION
1
INSPECT AIR FLOW FROM VENTS
•  Does air blow out?
Yes
Go to the next step.
No
Go to Step 1 of troubleshooting indexes No.1 and 2.
2
INSPECT A/C COMPRESSOR OPERATION
•  Start engine.
•  Turn A/C switch and fan switch on.
•  Does A/C compressor operate?
Yes
Go to Step 1 of troubleshooting index No.7.
No
Go to the next step.
3
INSPECT FOR DTC IN PCM
•  Inspect for DTCs related to the PCM on-board diagnostic system.
•  Are any DTCs displayed?
Yes
Go to appropriate inspection procedure.
No
Go to the next step.
4
INSPECT TO SEE WHETHER MALFUNCTION IS IN CLIMATE CONTROL UNIT OR ELSEWHERE
•  Does cool air blow out when terminal 1Q of front climate control unit connector (24-pin, A/C signal) is grounded?
Yes
Replace climate control unit, then go to Step 17.
No
Release short, then go to the next step (PCM connector (3 types)).
Release short, then go to step 6 (PCM connector (2 types)).
5
INSPECT TO SEE WHETHER MALFUNCTION IS IN REFRIGERANT PRESSURE SENSOR OR REFRIGERANT AMOUNT
•  Inspect refrigerant pressure sensor.
(See REFRIGERANT PRESSURE SENSOR INSPECTION.)
•  Is it okay?
Yes
Go to Step 10.
No
Go to the next step.
6
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 approx. 12 V?
Yes
Go to Step 8.
No
Go to the next step.
7
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (BETWEEN REFRIGERANT PRESSURE SWITCH AND PCM) OR PCM
•  Test voltage at A/C signal terminal of PCM.
•  Is voltage approx. 12 V?
Yes
Repair wiring harness between PCM and refrigerant pressure switch, then go to Step 17.
No
Inspect PCM, then go to Step 17.
8
INSPECT TO SEE WHETHER MALFUNCTION IS IN REFRIGERANT PRESSURE SWITCH, REFRIGERANT AMOUNT, OR ELSEWHERE
•  Does cool air blow out when terminals B and C of refrigerant pressure switch connector are shorted?
Yes
Go to the next step.
No
Go to Step 10.
9
INSPECT TO SEE WHETHER MALFUNCTION IS IN REFRIGERANT PRESSURE SWITCH OR REFRIGERANT AMOUNT
•  Inspect refrigerant pressure switch. (See REFRIGERANT PRESSURE SWITCH INSPECTION.)
•  Is it okay?
Yes
If refrigerant amount is empty, replace condenser, vacuum refrigerant line more than 30 min by vacuum pump, and add refrigerant to specified level, then go to Step 17.
No
Replace refrigerant pressure switch, then go to Step 17.
(See REFRIGERANT PRESSURE SWITCH REMOVAL/INSTALLATION[FULL-AUTO AIR CONDITIONER].)
10
INSPECT TO SEE WHETHER MALFUNCTION (SHORT CIRCUIT) 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
Repair or replace short circuit, then go to the next step.
No
Go to Step 12.
11*
INSPECT TO SEE WHETHER MALFUNCTION (OPEN OR SHORT CIRCUIT) 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 approx. 12 V?
Yes
Inspect 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 B (magnetic clutch operation signal)
•  Is voltage approx. 12 V?
Yes
Inspect magnetic clutch, then go to Step 17.
No
Go to the next step.
13
INSPECT FUSE
•  Are A/C relay power supply fuses okay?
Yes
Go to the next step.
No
Replace fuse, then go to Step 17. If fuse burns out immediately, go to the next step.
14
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 approx. 12 V?
Yes
Go to the next step.
No
Repair wiring harness between fuse block and A/C relay, then go to Step 17.
15
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 approx. 12 V?
Yes
Inspect wiring harness between A/C relay and magnetic clutch.
•  If above wiring harness is OK, go to the next step.
•  If above wiring harness malfunctions, repair wiring harness, then go to Step 17.
No
Replace A/C relay, then go to Step 17.
16
INSPECT EVAPORATOR TEMPERATURE SENSOR
•  Inspect evaporator temperature sensor.
•  Is it okay?
Yes
Go to the next step.
No
Replace evaporator temperature sensor, then go to the next step.
17
VERIFY REPAIR
•  Does cool air blow out from front/rear vents? (Are the results of refrigerant system performance test okay?)
Yes
Troubleshooting completed. Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.