Dtc B1479/79 Flow Sensor Circuit

Vehicle Interior. Corolla. Zre142 Aze141
Heating Air Conditioning. Corolla. Zre142 Aze141

DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING TECHSTREAM

READ VALUE USING TECHSTREAM

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

CHECK HARNESS AND CONNECTOR (COMPRESSOR ASSEMBLY WITH PULLEY - A/C AMPLIFIER)

DTC B1479/79 Flow Sensor Circuit


DESCRIPTION

The A/C flow sensor, which is mounted on the compressor assembly with pulley, 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 it to the A/C amplifier. 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 A/C amplifier supplies 5 V to the A/C flow sensor and monitors change in the voltage value sent from the A/C flow sensor. The A/C amplifier 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
  1. Compressor assembly with pulley (A/C flow sensor)
  2. Harness or connector between compressor assembly with pulley (A/C flow sensor) and A/C amplifier
  3. A/C amplifier

WIRING DIAGRAM


Corolla. Zre142 Aze141.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System). Dtc B1479/79 Flow Sensor Circuit


INSPECTION PROCEDURE

1.READ VALUE USING TECHSTREAM

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

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

  1. Check the value(s) by referring to the table below.

    Air Conditioner
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Flow Sensor
    (Flow Sens)
    		A/C flow sensor /
    Min.: 0 V
    Max.: 5 V
    		A/C on, Blower switch HI: 0.7 to 3.8 V
    A/C off, Blower switch off: 3.8 to 4.2 V
    		A/C flow sensor is malfunctioning when a constant value below 0.7 V or higher than 4.2 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
REPLACE AIR CONDITIONING AMPLIFIER (COROLLA_ZRE142 RM000002XMC01VX.html)

C
Go to step 3
A


2.READ VALUE USING TECHSTREAM

  1. Connect the Techstream to the DLC3.

  1. Turn the ignition switch to ON.

  1. Turn the Techstream on.

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

  1. 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
    Operation does not match normal condition column
    		A
    Operation matches normal condition column
    		B


B
PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (COROLLA_ZRE142 RM000001M2W05OX.html)
A


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

  1. Replace the compressor assembly with pulley (A/C flow sensor) (COROLLA_ZRE142 RM000002XUM022X.html).

    HINT:
    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 a known good one and check that the condition returns to normal.

  1. Check for the DTC.

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


B
Go to step 4
A

END

4.CHECK HARNESS AND CONNECTOR (COMPRESSOR ASSEMBLY WITH PULLEY - A/C AMPLIFIER)

  1. Disconnect the A/C amplifier connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    E30-7 (FLOQ) - B97-3 (QUFL)
    		Always
    		Below 1 Ω
    E30-35 (SG-4) - B97-2 (SGFL)
    		Always
    		Below 1 Ω
    E30-30 (S5-1) - B97-1 (S5FL)
    		Always
    		Below 1 Ω
    E30-7 (FLOQ) - Body ground
    		Always
    		10 kΩ or higher
    E30-35 (SG-4) - Body ground
    		Always
    		10 kΩ or higher
    E30-30 (S5-1) - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER (COROLLA_ZRE142 RM000002XMC01VX.html)