AIR CONDITIONING SYSTEM, Diagnostic DTC:B1479/79

DTC Code DTC Name
B1479/79 Flow Sensor Circuit

DESCRIPTION

The A/C flow sensor, which is mounted on the compressor, is used to detect the amount of refrigerant flow. The A/C flow sensor converts the amount of refrigerant flow that is detected to a voltage value to send to the air conditioning amplifier assembly. The voltage value sent from the A/C flow sensor changes depending on the amount of refrigerant flow. As the amount of refrigerant flow becomes larger, the voltage becomes lower. As the amount of refrigerant flow becomes smaller, the voltage becomes higher. The air conditioning amplifier assembly supplies 5 V to the A/C flow sensor and monitors changes in the voltage value sent from the A/C flow sensor. The air conditioning amplifier assembly then sends a signal to the ECM via CAN communication to allow the ECM to control the engine speed while the air conditioning is on.

DTC No. DTC Detection Condition Trouble Area
B1479/79 Open or short in A/C flow sensor circuit

  • Compressor assembly with pulley (A/C flow sensor)*1

  • Cooler compressor assembly (A/C flow sensor)*2

  • Harness or connector between compressor assembly with pulley (A/C flow sensor) and air conditioning amplifier assembly*1

  • Harness or connector between Cooler compressor assembly (A/C flow sensor) and air conditioning amplifier assembly*2

  • Air conditioning amplifier assembly

WIRING DIAGRAM

B001O5LE25

PROCEDURE


  1. CONFIRM MODEL

    Result
    Result Proceed to
    except 2GR-FE A
    for 2GR-FE B

    B

    READ VALUE USING GTS Click here

    A

  2. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Air Conditioner / Data List.

    5. Read the Data List according to the display on the GTS.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Flow Sensor

      A/C flow sensor /

      Min.: 0.0 V

      Max.: 5.0 V

      		 Ignition switch ON: 0.3 to 4.7 V Flow sensor is malfunctioning when a constant value below 0.3 V or higher than 4.7 V is displayed continuously for more than 4 seconds.
      OK
      The display is as specified in the Normal Condition column.
      Result
      Result Proceed to
      OK (When troubleshooting according to Problem Symptoms Table) A
      OK (When troubleshooting according to the DTC) B
      NG (When a constant value between 0.7 and 4.2 V is displayed continuously for more than 4 seconds) C

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    C

    REPLACE COMPRESSOR ASSEMBLY WITH PULLEY (A/C FLOW SENSOR) Click here

    A

  3. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Air Conditioner / Data List.

    5. Read the Data List according to the display on the GTS.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      A/C Cutoff Signal

      A/C control cutoff signal /

      OFF or ON

      		 The ECM sends the air conditioning control cutoff signal displayed -
      Result
      Result Proceed to
      Value in Data List indicates OFF A
      Value in Data List indicates ON B

    B

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    A

  4. REPLACE COMPRESSOR ASSEMBLY WITH PULLEY (A/C FLOW SENSOR)


    1. Replace the compressor assembly with pulley (A/C flow sensor) Click here.

      Tech Tips

      Since the compressor assembly with pulley (A/C flow sensor) cannot be inspected while it is removed from the vehicle, replace the compressor assembly with pulley (A/C flow sensor) with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Result
      Result Proceed to
      DTC B1479/79 is not output A
      DTC B1479/79 is output B

    A

    END

    B

  5. CHECK HARNESS AND CONNECTOR (COMPRESSOR ASSEMBLY WITH PULLEY (A/C FLOW SENSOR) - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the H54 air conditioning amplifier assembly connector.

    2. Disconnect the D67 compressor assembly with pulley (A/C flow sensor) connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H54-7 (FLOQ) - D67-3 (QUFL) Always Below 1 Ω
      H54-13 (SG-2) - D67-2 (SGFL) Always Below 1 Ω
      H54-30 (S5-1) - D67-1 (S5FL) Always Below 1 Ω
      H54-7 (FLOQ) - Body ground Always 10 kΩ or higher
      H54-13 (SG-2) - Body ground Always 10 kΩ or higher
      H54-30 (S5-1) - Body ground Always 10 kΩ or higher

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR

  6. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Air Conditioner / Data List.

    5. Read the Data List according to the display on the GTS.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Flow Sensor

      A/C flow sensor /

      Min.: 0.0 V

      Max.: 5.0 V

      		 Ignition switch ON: 0.3 to 4.7 V Flow sensor is malfunctioning when a constant value below 0.3 V or higher than 4.7 V is displayed continuously for more than 4 seconds.
      OK
      The display is as specified in the Normal Condition column.
      Result
      Result Proceed to
      OK (When troubleshooting according to Problem Symptoms Table) A
      OK (When troubleshooting according to the DTC) B
      NG (When a constant value between 0.7 and 4.2 V is displayed continuously for more than 4 seconds) C

    B

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    C

    REPLACE COOLER COMPRESSOR ASSEMBLY (A/C FLOW SENSOR) Click here

    A

  7. READ VALUE USING GTS


    1. Connect the GTS to the DLC3.

    2. Turn the engine switch on (IG).

    3. Turn the GTS on.

    4. Enter the following menus: Body Electrical / Air Conditioner / Data List.

    5. Read the Data List according to the display on the GTS.

      Air Conditioner
      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      A/C Cutoff Signal

      A/C control cutoff signal /

      OFF or ON

      		 The ECM sends the air conditioning control cutoff signal displayed -
      Result
      Result Proceed to
      Value in Data List indicates OFF A
      Value in Data List indicates ON B

    B

    PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE Click here

    A

  8. REPLACE COOLER COMPRESSOR ASSEMBLY (A/C FLOW SENSOR)


    1. Replace the cooler compressor assembly (A/C flow sensor) Click here.

      Tech Tips

      Since the cooler compressor assembly (A/C flow sensor) cannot be inspected while it is removed from the vehicle, replace the cooler compressor assembly (A/C flow sensor) with a new or known good one and check that the condition returns to normal.

    2. Check for DTCs.

      Result
      Result Proceed to
      DTC B1479/79 is not output A
      DTC B1479/79 is output B

    A

    END

    B

  9. CHECK HARNESS AND CONNECTOR (COOLER COMPRESSOR ASSEMBLY (A/C FLOW SENSOR) - AIR CONDITIONING AMPLIFIER ASSEMBLY)


    1. Disconnect the H54 air conditioning amplifier assembly connector.

    2. Disconnect the D67 cooler compressor assembly (A/C flow sensor) connector.

    3. Measure the resistance according to the value(s) in the table below.

      Standard Resistance
      Tester Connection Condition Specified Condition
      H54-7 (FLOQ) - D67-3 (QUFL) Always Below 1 Ω
      H54-13 (SG-2) - D67-2 (SGFL) Always Below 1 Ω
      H54-30 (S5-1) - D67-1 (S5FL) Always Below 1 Ω
      H54-7 (FLOQ) - Body ground Always 10 kΩ or higher
      H54-13 (SG-2) - Body ground Always 10 kΩ or higher
      H54-30 (S5-1) - Body ground Always 10 kΩ or higher

    OK

    REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY Click here

    NG

    REPAIR OR REPLACE HARNESS OR CONNECTOR