INSPECTION
PROCEDURE 2: Cool air does not come <Front side>
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If the blower air temperature can not be cool when turning A/C switch ON and
lowering the preset temperature, inadequate refrigerant quantity, sensors, harness or connectors
may be suspected.
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- The refrigerant quantity is inadequate.
- Damaged harness wires and connectors
- Malfunction of the blower motor
- Malfunction of the fin thermo sensor
- Malfunction of the heater controller assembly (A/C-ECU)
- Malfunction of the engine-ECU
- Malfunction of the dual pressure switch
- Malfunction of the A/C compressor and clutch
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STEP 1. M.U.T.-III CAN bus diagnostics.
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Use the M.U.T.-III to diagnose the CAN bus lines.
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Q.
Is the check result normal?
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Go to Step 2.
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Repair the CAN bus lines. (Refer to GROUP 54C - Troubleshooting ).
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STEP 2. M.U.T.-III diagnosis code for heater controller assembly (A/C-ECU).
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Check that the diagnosis code related to the air conditioner is not set.
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Q.
Is the diagnosis code set?
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Carry out the diagnosis code procedures (Refer to ).
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Go to Step 3.
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STEP 3. Check the M.U.T.-III diagnosis code for engine-ECU.
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Check whether the engine-ECU sets any of the diagnosis codes below:
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P0537: Air thermo sensor circuit low input P0538: Air thermo sensor circuit high input
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Q.
Is the diagnosis code set?
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YES <6B3> : Carry out the diagnosis code procedures (Refer to GROUP 13B - Code No.
P0537: Air thermo sensor circuit low input , Code No. P0538: Air
thermo sensor circuit high Input ).
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YES <4N1> : Carry out the diagnosis code procedures (Refer to GROUP 13C - Code No.
P0537: A/C evaporator temperature sensor circuit low input ,
Code No. P0538: A/C evaporator temperature sensor circuit high input ).
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Go to Step 4.
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STEP 4. Check the blower operation.
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Check that air blows through the air outlets.
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(1)Turn the ignition switch to the ON position.
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(2)Fan mode changeover switch: Other than OFF
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(3)Check that the air comes out of the blower.
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Q.
Is the check result normal?
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Go to Step 5.
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Refer to Inspection Procedure 4 "The blower does not work <Front side>" .
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STEP 5. Check the A/C compressor operation.
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Check that the compressor operates under the following conditions.
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- Engine operation
- Fan mode changeover switch: Maximum air volume
- Temperature set switch: MAX COOL (18.0°C)
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Q.
Is the check result normal?
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Go to Step 6.
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Refer to Inspection Procedure 9 "The A/C compressor and clutch assembly
does not work" .
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STEP 6. Refrigerant level check.
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Check that the refrigerant level is adequate (Refer to GROUP 55A - Refrigerant
Level Check, Draining and Charging ).
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Q.
Is the check result normal?
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YES : Go to Step 7.
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Correct the refrigerant amount.
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STEP 7. Check the dual pressure switch.
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Refer to GROUP 55A - Pressure Switch Check .
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Q.
Is the dual pressure switch in good condition?
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Go to Step 8.
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Replace the dual pressure switch (Refer to ).
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STEP 8. Voltage measurement at dual pressure switch connector.
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Voltage between terminal 1 and body earth. OK: System voltage
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Q.
Is the check result normal?
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Go to Step 10.
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Go to Step 9.
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STEP 9. Check of open circuit in dual pressure switch line between
dual pressure switch connector AC/S terminal and engine-ECU connector.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 10. Voltage measurement at heater controller assembly (A/C-ECU).
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(1)Disconnect the connector, and measure at the wiring harness side.
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(2)Turn the ignition switch to the "ON" position.
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(3)Voltage between terminal 10 and body earth. OK: System voltage
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Q.
Is the check result normal?
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Go to Step 12.
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Go to Step 11.
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STEP 11. Check of open circuit in A/C line between heater controller
assembly (A/C-ECU) connector A/C terminal and dual pressure switch connector.
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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Repair or replace the connector(s) or wiring harness.
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STEP 12. Retest the system
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Q.
Is the check result normal?
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Intermittent malfunction (Refer to GROUP 00 - How to Cope with Intermittent
Malfunction ).
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NO <6B3> : Replace the engine-ECU (Refer to GROUP 13B - Engine-ECU ).
Then go to Step 13.
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NO <4N1> : Replace the engine-ECU (Refer to GROUP 13C - Engine-ECU ).
Then go to Step 13.
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STEP 13. Retest the system
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Q.
Is the check result normal?
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This diagnosis is complete.
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Replace the heater controller assembly (A/C-ECU) (Refer to ).
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