NO.8 NO COOL AIR

id070300801100

8
No cool air
DESCRIPTION
•  Magnetic clutch does not operate.
POSSIBLE CAUSE
•  Malfunction in PCM A/C cut control system
•  Malfunction in climate control unit
•  Malfunction in refrigerant pressure switch
•  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
•  Malfunction in BCM unit (Manual A/C)
•  Malfunction in CAN communication

•  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 BLOW OUT
•  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 airflow volume control dial 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
(Auto A/C)
Go to the next step.
(Manual A/C)
Go to Step 5.
4
CONFIRM DTC U0073, U0516 USING M-MDS
•  Retrieve DTC from EATC and HEC.
•  DTCs (U0073, U0516) retrieved?
Yes
Network communication, for related system is malfunction.
Go to appropriate inspection procedure.
No
Go to Step 6.
5
INSPECT TO SEE WHETHER MALFUNCTION IS IN PCM OR ELSEWHERE
•  Does cool air blow out when terminal 1AU of PCM connector (24-pin, A/C signal) is grounded?
Yes
Inspect and/or replace the PCM, then go to Step 18.
No
Release short, then 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 (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 approx. 12 V?
Yes
Repair wiring harness between PCM and refrigerant pressure switch, then go to Step 18.
No
Inspect PCM, then go to Step 18.
8
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?
Yes
Go to Step 10.
No
(Auto A/C)
Go to Step 11.
(Manual A/C)
Go to the next step.
9*
INSPECT TO SEE WHETHER MALFUNCTION IS IN WIRING HARNESS (BETWEEN REFRIGERANT PRESSURE SWITCH AND PCM) OR ELSEWHERE
•  Test voltage at following terminal of PCM.
―  Terminal 1AU (A/C signal)
•  Is voltage approx. 12 V?
Yes
Go to Step 11.
No
Repair wiring harness between refrigerant pressure switch and climate control unit, then go to Step 18.
10
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, vacuum refrigerant line more than 30 min by vacuum pump, and add refrigerant to specified level, then go to Step 18.
No
Replace refrigerant pressure switch, then go to Step 18.
11
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 the next step.
No
Go to Step 13.
12*
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 approx. 12 V?
Yes
Inspect PCM, then go to Step 18.
No
Repair wiring harness between A/C relay and PCM, then go to Step 18.
13*
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 approx. 12 V?
Yes
Inspect magnetic clutch, then go to Step 18.
No
Go to the next step.
14
INSPECT FUSE
•  Are A/C relay power supply fuses okay?
Yes
Go to the next step.
No
Replace fuse, then go to Step 18. If fuse burns out immediately, go to the next step.
15
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 18.
16
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 18.
No
Replace A/C relay, then go to Step 18.
17
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.
18
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.
No
Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.