DTC    B1479    Flow Sensor Circuit

for Preparation Click here


DESCRIPTION

The flow sensor is built into the compressor, and outputs a signal indicating the flow rate of the refrigerant. The air conditioning amplifier converts the received signal to refrigerant flow rate data according to the characteristics of the sensor, which it then sends to the ECM via CAN communication.

DTC No.
DTC Detection Condition
Trouble Area
B1479
  1. The ignition switch is ON*1, the A/C is on and the flow sensor circuit has an open or short circuit.
  2. The ignition switch is ON*1 and the flow sensor is stuck.
  1. Air conditioning compressor (flow sensor)
  2. Harness and connector between flow sensor and air conditioning amplifier
  3. Air conditioning amplifier
*1: As the flow sensor measures the flow rate of the refrigerant in the air conditioning system, it is necessary to turn the ignition switch to ON in order to check the state of the flow sensor.

WIRING DIAGRAM


E174031E03


INSPECTION PROCEDURE

NOTICE:
This DTC is stored when there is no refrigerant in the system, so check refrigerant volume and pressure first when this DTC is output (Click here).

1.READ VALUE USING INTELLIGENT TESTER (FLOW SENSOR)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

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

  1. According to the display on the intelligent tester, read the Data List.

    Air Conditioning 
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Flow sensor
    		Flow sensor/
    Min.: 0.0 V, Max.: 5.0 V
    		Flow sensor voltage displayed
    		Open circuit: 4.7 V or more
    Short circuit: 0.3 V or less

    Result 
    Result
    		Proceed to
    4.7 V or more: Open circuit
    (A/C is on)
    		A
    0.3 V or less: Short circuit
    (A/C is on)
    		A
    Circuit is not open or shorted
    		B



B
Go to step 5
A


2.CHECK HARNESS AND CONNECTOR (FLOW SENSOR - AIR CONDITIONING AMPLIFIER)


    E177086E01

  1. Disconnect the B33 air conditioning compressor (flow sensor) connector.

  1. Disconnect the D16 air conditioning amplifier connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    B33-6 (QUFL) - D16-4 (FLOQ)
    		Always
    		Below 1 Ω
    B33-4 (S5FL) - D16-7 (S5-3)
    		Always
    		Below 1 Ω
    B33-5 (SGFL) - D16-23 (SG-1)
    		Always
    		Below 1 Ω
    D16-4 (FLOQ) - Body ground
    		Always
    		10 kΩ or higher
    D16-7 (S5-3) - Body ground
    		Always
    		10 kΩ or higher
    D16-23 (SG-1) - Body ground
    		Always
    		10 kΩ or higher

  1. Reconnect the air conditioning compressor (flow sensor) connector.

  1. Reconnect the air conditioning amplifier connector.

Text in Illustration 
*1
Front view of wire harness connector
(to Air Conditioning Compressor (Flow Sensor))
*2
Front view of wire harness connector
(to Air Conditioning Amplifier)


NG
REPAIR OR REPLACE HARNESS AND CONNECTOR
OK


3.REPLACE AIR CONDITIONING COMPRESSOR (FLOW SENSOR)

  1. for 1KR-FE

    1. Replace the air conditioning compressor (flow sensor) with a normal one (Click here).

  1. for 1ND-TV

    1. Replace the air conditioning compressor (flow sensor) with a normal one (Click here).


NEXT


4.CHECK FOR DTC

  1. Clear the DTCs (Click here).

  1. Check for DTCs (Click here).

    OK:
    DTC B1479 is not output.



NG
REPLACE AIR CONDITIONING AMPLIFIER (Click here)
OK

END (AIR CONDITIONING COMPRESSOR (FLOW SENSOR) IS FAULTY) 

5.READ VALUE USING INTELLIGENT TESTER (FLOW SENSOR)

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the intelligent tester on.

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

  1. According to the display on the intelligent tester, read the Data List.

    Air Conditioner 
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Flow sensor
    		Flow sensor/
    Min.: 0.0 V, Max.: 5.0 V
    		Flow sensor voltage displayed
    		Open circuit: 4.7 V or more
    Short circuit: 0.3 V or less

    Result 
    Result
    		Proceed to
    Sensor is stuck in an intermediate position
    1. Engine idling
    2. A/C switch off
    3. Sensor voltage is 3.76 V or less and does not change for 8.5 minutes or more
    		A
    Sensor is stuck at zero position
    1. Engine idling
    2. A/C switch on
    3. Sensor voltage is 3.76 V or more and does not change for 8.5 minutes or more
    		A
    Sensor is not stuck (When troubleshooting according to the Problem Symptoms Table)
    		B
    Sensor is not stuck (When troubleshooting according to the DTC output)
    		C



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

C
Go to step 8
A


6.CHECK REFRIGERANT PRESSURE

  1. Install the manifold gauge set.

  1. Read the gauge pressure to check that refrigerant has been charged (Click here).

OK:
Refrigerant is charged.



NG
CHARGE REFRIGERANT
OK


7.REPLACE AIR CONDITIONING COMPRESSOR(FLOW SENSOR)

  1. for 1KR-FE

    1. Replace the air conditioning compressor (flow sensor) with a normal one (Click here).

NOTICE:
In some cases, this DTC is stored when the magnetic clutch is not functioning properly, so inspect the magnet clutch clearance before replacing the air conditioning compressor (flow sensor) (Click here(for 1KR-FE).

  1. for 1ND-TV

    1. Replace the air conditioning compressor (flow sensor) with a normal one (Click here).

NOTICE:
In some cases, this DTC is stored when the magnet clutch assembly is not functioning properly, so inspect the magnet clutch before replacing the flow sensor(air conditioning compressor assembly) (Click here(for 1ND-TV).


OK


8.CHECK FOR DTC

  1. Clear the DTCs (Click here).

  1. Check for DTCs (Click here).

OK:
DTC B1479 is not output.



NG
REPLACE AIR CONDITIONING AMPLIFIER (Click here)
OK

END (AIR CONDITIONING COMPRESSOR (FLOW SENSOR) IS FAULTY)