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Home >> Toyota >> 2012 >> Highlander Limited, FWD >> Repair and Diagnosis >> Heating, Ventilation & A/C (HVAC) >> HVAC Control Systems >> Air Conditioning (Automatic) (Diagnostic Codes & Circuit Tests) (Except Hybrid) >> AIR CONDITIONING SYSTEM (for Automatic Air Conditioning System) >> DTC B1479/79: Flow Sensor Circuit >> Procedure

DTC B1479/79: Flow Sensor Circuit: Procedure

  1. READ VALUE USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Air Conditioner / Data List.
    5. Check the value(s) by referring to the table below.
      AIR CONDITIONER

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      Flow Sensor A/C flow sensor /
      Min.: 0 V
      Max.: 5 V      		 Ignition switch on (IG): 0.3 to 4.7 V A/C 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 below 0.3 V or higher than 4.7 V is displayed continuously for more than 4 seconds) C

    B → See step   5 

    C → See step   3 

    A: Go to next step 

  2. READ VALUE USING TECHSTREAM 
    1. Connect the Techstream to the DLC3.
    2. Turn the ignition switch on (IG).
    3. Turn the Techstream on.
    4. Enter the following menus: Body Electrical / Air Conditioner / Data List.
    5. Check the value(s) by referring to the table below.
      AIR CONDITIONER

      Tester Display Measurement Item/Range Normal Condition Diagnostic Note
      A/C Cutoff Signal A/C control cutoff signal /
      OFF or ON      		 A/C switch on: OFF
      A/C switch off: ON      		 -

      Result

      Result Proceed to
      Value in Data List indicates OFF A
      Value in Data List indicates ON B

    B → See step   6 

    A: Go to next step 

  3. REPLACE COMPRESSOR AND MAGNETIC CLUTCH (A/C FLOW SENSOR) 
    1. Replace the A/C compressor (A/C flow sensor). Refer to REMOVAL .

      HINT: 

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

    2. Check for the DTC.

      Result

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

    B → See step   4 

    A → END 

  4. CHECK HARNESS AND CONNECTOR (COMPRESSOR AND MAGNET (A/C FLOW SENSOR) - A/C AMPLIFIER) 
    1. Disconnect the A/C amplifier connector.
      Fig 1: Checking Harness And Connector (Compressor And Magnet (A/C Flow Sensor) - A/C Amplifier)
      GTY299304Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002
    2. Measure the resistance according to the value(s) in the table below.
      Fig 2: Measuring Resistance Of Compressor & Magnetic Clutch A/C Flow Sensor
      GTY303896Courtesy of © TOYOTA, LICENSE AGREEMENT TMS1002

      Standard Resistance

      Tester Connection Condition Specified Condition
      D37-7 (FLOQ) - B67-3 (QUFL) Always Below 1 Ω
      D37-13 (SG-2) - B67-2 (SGFL) Always Below 1 Ω
      D37-30 (S5-1) - B67-1 (S5FL) Always Below 1 Ω
      D37-7 (FLOQ) - Body ground Always 10 kΩ or higher
      D37-13 (SG-2) - Body ground Always 10 kΩ or higher
      D37-30 (S5-1) - Body ground Always 10 kΩ or higher

    NG → REPAIR OR REPLACE HARNESS OR CONNECTOR 

    OK → See step   5 

  5. REPLACE A/C AMPLIFIER. Refer to  REMOVAL 
  6. PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE. Refer to  PROBLEM SYMPTOMS TABLE 
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