Dtc B1419/19 Rear Room Temperature Sensor Circuit


DESCRIPTION

WIRING DIAGRAM

INSPECTION PROCEDURE

READ VALUE USING INTELLIGENT TESTER (REAR ROOM TEMPERATURE SENSOR)

INSPECT COOLER THERMISTOR (REAR ROOM TEMPERATURE SENSOR)

CHECK HARNESS AND CONNECTOR (REAR ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)

DTC B1419/19 Rear Room Temperature Sensor Circuit


DESCRIPTION

The cooler thermistor (rear room temperature sensor) is installed in the rear panel. It detects the rear cabin temperature to control the air conditioning AUTO mode. The resistance of the cooler thermistor (rear room temperature sensor) changes in accordance with the rear cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.
The air conditioning amplifier assembly applies a voltage (5 V) to the cooler thermistor (rear room temperature sensor) and reads voltage changes as the resistance of the cooler thermistor (rear room temperature sensor) changes.

DTC Code
DTC Detection Condition
Trouble Area
B1419/19
Open or short in the cooler thermistor (rear room temperature sensor) circuit.
  1. Cooler thermistor (rear room temperature sensor)
  2. Harness or connector
  3. Air conditioning amplifier assembly

WIRING DIAGRAM


Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System). Dtc B1419/19 Rear Room Temperature Sensor Circuit


INSPECTION PROCEDURE

1.READ VALUE USING INTELLIGENT TESTER (REAR ROOM TEMPERATURE SENSOR)

  1. Use the Data List to check if the rear room temperature sensor is functioning properly (LandCruiser RM000002LIV040X.html).

    Air Conditioner
    Tester Display
    		Measurement Item/Range
    		Normal Condition
    		Diagnostic Note
    Room Temp Sensor (Rear)
    		Cooler thermistor (rear room temperature sensor) /
    Min.: -6.5°C (20.3°F)
    Max.: 57.25°C (135.05°F)
    		Actual rear cabin temperature displayed
    		Open in the circuit: -6.5°C (- 20.3°F).
    Short in the circuit: 57.25°C (135.05°F).
    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
    		C


B
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (LandCruiser RM0000039R5028X.html)

C
Go to step 2
A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE (LandCruiser RM0000045E302NX.html)

2.INSPECT COOLER THERMISTOR (REAR ROOM TEMPERATURE SENSOR)


  1. Remove the cooler thermistor (rear room temperature sensor) (LandCruiser RM000001A3T01ZX.html).


    Land Cruiser, Land Cruiser Prado. Grj150 Trj150,155 Kdj150,155 Lj150, Gdj150,155.Heating Air Conditioning.Air Conditioning System (For Automatic Air Conditioning System). Dtc B1419/19 Rear Room Temperature Sensor Circuit


    Text in Illustration
    *a
    		Resistance
    		*b
    		Allowable Range
    *c
    		Temperature
    		-
    		-

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    1 - 2
    		10°C (50°F)
    		3.00 to 3.73 kΩ
    15°C (59°F)
    		2.45 to 2.88 kΩ
    20°C (68°F)
    		1.95 to 2.30 kΩ
    25°C (77°F)
    		1.60 to 1.80 kΩ
    30°C (86°F)
    		1.28 to 1.47 kΩ
    35°C (95°F)
    		1.00 to 1.22 kΩ
    40°C (104°F)
    		0.80 to 1.00 kΩ
    45°C (113°F)
    		0.65 to 0.85 kΩ
    50°C (122°F)
    		0.50 to 0.70 kΩ
    55°C (131°F)
    		0.44 to 0.60 kΩ
    60°C (140°F)
    		0.36 to 0.50 kΩ
    NOTICE:
    1. Even slightly touching the sensor may change the resistance value. Be sure to hold the connector of the sensor.
    2. When measuring, the sensor temperature must be the same as the ambient temperature.
    HINT:
    As the temperature increases, the resistance decreases (refer to the graph).


NG
REPLACE COOLER THERMISTOR (REAR ROOM TEMPERATURE SENSOR) (LandCruiser RM000001A3T01ZX.html)
OK


3.CHECK HARNESS AND CONNECTOR (REAR ROOM TEMPERATURE SENSOR - AIR CONDITIONING AMPLIFIER)

  1. Disconnect the G24 amplifier connector.

  1. Disconnect the Q19 sensor connector.

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

    Standard Resistance:
    Tester Connection
    		Condition
    		Specified Condition
    Q19-1 - G24-17 (TR)
    		Always
    		Below 1 Ω
    Q19-2 - G24-7 (SG-6)
    		Always
    		Below 1 Ω
    Q19-1 - Body ground
    		Always
    		10 kΩ or higher
    Q19-2 - Body ground
    		Always
    		10 kΩ or higher


NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY (LandCruiser RM0000039R5028X.html)