NO.5 NO COOL AIR

id070300802600

5

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

• 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

Inspection item (s)

1

INSPECT AIR BLOW OUT

• Does air blow out?
Yes
Go to next step.
No
Go to Step 1 of troubleshooting index No.1.
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.4.
No
Go to 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 next step.
4

INSPECT TO SEE WHETHER MALFUNCTION IS IN CLIMATE CONTROL UNIT OR ELSEWHERE

• Does cool air blow out when terminal 1K of climate control unit connector (16-pin, A/C signal) is grounded?
Yes
Replace climate control unit, then go to Step 16.
No
Release short, then go to next step.
5*

INSPECT TO SEE WHETHER MALFUNCTION IS IN A/C SIGNAL CIRCUIT (BETWEEN A/C CYCLING SWITCH AND PCM) OR ELSEWHERE

• Test voltage at following terminal of A/C cycling switch.
- Terminal B (A/C signal)
• Is voltage approx. 12 V?
Yes
Go to Step 7.
No
Go to next step.
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 approx. 12 V?
Yes
Repair wiring harness between PCM and refrigerant pressure switch, then go to Step 16.
No
Inspect PCM, then go to Step 16.
7

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

• Does cool air blow out when terminals C and D of refrigerant pressure switch connector are shorted?
Yes
Go to Step 9.
No
Go to next step.
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 1K (16-pin, A/C signal)
• Is voltage approx. 12 V?
Yes
Go to Step 10.
No
Repair wiring harness between refrigerant pressure switch and climate control unit, then go to Step 16.
9

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

• Inspect refrigerant pressure switch.
• Is it normal?
Yes
If refrigerant amount is empty, replace condenser, vacuum refrigerant line 30 min or more by vacuum pump, and add refrigerant to specified level, then go to Step 16.
No
Replace refrigerant pressure switch, then go to Step 16.
10

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.
No
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 approx. 12 V?
Yes
Inspect PCM, then go to Step 16.
No
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.
- Terminal A (magnetic clutch operation signal)
• Is voltage approx. 12 V?
Yes
Inspect magnetic clutch, then go to Step 16.
No
Go to next step.
13

INSPECT FUSE

• Are A/C relay power supply fuses normal?
Yes
Go to next step.
No
Replace fuse, then go to Step 16. If fuse burns out immediately, go to 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 D (A/C control signal)
• Are voltages approx. 12 V?
Yes
Go to next step.
No
Repair wiring harness between fuse block and A/C relay, then go to Step 16.
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 normal, go to next step.
• If above wiring harness malfunctions, repair wiring harness, then go to Step 16.
No
Replace A/C relay, then go to Step 16.
16

CONFIRM THAT MALFUNCTION SYMPTOMS DO NOT RECUR AFTER REPAIR

• Does cool air blow out? (Are the results of refrigerant system performance test normal?)
Yes
Troubleshooting completed. Explain repairs to customer.
No
Recheck malfunction symptoms, then repeat from Step 1 if malfunction recurs.