RX400h · Service Manual HEATER & AIR CONDITIONING SYSTEM

B1421/21

Diagnostic trouble codes

DESCRIPTION

E109314E01
The automatic light control sensor is installed in the upper part of the instrument panel to detect the amount of solar sensor radiation with photo diode to control the heater and air conditioner "AUTO" function. It sends appropriate signals to the A/C amplifier assembly. The output voltage of the automatic light control sensor changes in accordance with the amount of solar radiation. As the amount increases, the voltage increases. As the amount decreases, the voltage decreases. The A/C amplifier assembly reads voltage output from the automatic light control sensor.
DTC No.
 DTC Detecting Condition
 Trouble Area
B1421/21
 Open or short in solar sensor circuit
(If the check is performed in a dark place, DTC B1421/21 may be displayed.)
  1. Automatic light control sensor
  2. Harness or connector between automatic light control sensor and A/C amplifier assembly and multiplex network body ECU
  3. A/C amplifier assembly

HINT:
If DTC B1244 is output at the same time, troubleshoot DTC B1244 first.


WIRING DIAGRAM

E109253E03

INSPECTION PROCEDURE


1. READ VALUE OF INTELLIGENT TESTER

  1. Connect the intelligent tester to the DLC3.

  1. Turn the ignition switch ON and push the intelligent tester main switch on.

  1. Select the item below in the DATA LIST, and read the display on the intelligent tester.

DATA LIST / AIR CONDITIONER 
Item
 Measurement Item/Display
(Symbols)
 Normal Condition
 Diagnostic Note
SOLAR SENS-P
 Solar sensor (Passenger side) / min.: 0 max.: 255
 Increases as brightness increases
 Open in the circuit: 0
Short in the circuit: 255

OK:
The display is as specified in the normal condition.


Result:
Result
 Proceed to
NG
 A
OK (Checking from the PROBLEM SYMPTOMS TABLE)
 B
OK (Checking from the DTC)
 C



B
PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE

C
REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
A


2. INSPECT MULTIPLEX NETWORK BODY ECU

  1. E108941E05
    Remove the multiplex network body ECU with the connectors still connected.

  1. Turn the ignition switch to the ON position.

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    B6-6 (CLTB) - B6-4 (CLTE)
    		 Ignition switch ON
    		 10 to 14 V



OK
Go to step 4
NG


3. CHECK HARNESS AND CONNECTOR (AUTOMATIC LIGHT CONTROL SENSOR - MULTIPLEX NETWORK BODY ECU)

  1. E108942E05
    Disconnect the connector from the automatic light control sensor and multiplex network body ECU.

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

    Resistance:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    A13-6 (CLTB) - B6-6 (CLTB)
    		 Always
    		 Below 1 Ω
    A13-3 (CLTE) - B6-4 (CLTE)
    		 Always
    		 Below 1 Ω
    A13-6 (CLTB) - Body ground
    		 Always
    		 10 kΩ or higher
    A13-3 (CLTE) - Body ground
    		 Always
    		 10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE MULTIPLEX NETWORK BODY ECU

4. CHECK HARNESS AND CONNECTOR (AUTOMATIC LIGHT CONTROL SENSOR - A/C AMPLIFIER ASSEMBLY)

  1. E108943E05
    Disconnect the connector from the A/C amplifier assembly.

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

    Resistance:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    A11-11 (TSP) - A13-2 (TSR)*1
    		Always
    		 Below 1 Ω
    A11-11 (TSP) - A13-1 (TSR)*2
    		Always
    		 Below 1 Ω
    A11-11 (TSP) - Body ground
    		 Always
    		 10 kΩ or higher

    1. *1: LHD
    2. *2: RHD



 NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK


5. INSPECT AUTOMATIC LIGHT CONTROL SENSOR

  1. E109215E03
    Remove the automatic light control sensor.

  1. Apply battery voltage between terminals A13-6 (CLTB) and A13-3 (CLTE) of the automatic light control sensor.

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

    Voltage:
    Tester connection
    (Symbols)
    		 Condition
    		 Specified condition
    A13-6 (CLTB) - A13-3 (CLTE)
    		 Sensor is subject to electric light
    		 0.8 to 4.3 V
    A13-6 (CLTB) - A13-3 (CLTE)
    		 Sensor is covered with a cloth
    		 Below 0.8 V

    NOTICE:
    The connection procedure for using a digital tester such as a TOYOTA electrical tester is shown above. When using an analog tester, connect the positive (+) lead to terminal 2 and negative (-) lead to terminal 1 of the automatic light control sensor.

    HINT:
    1. As the inspection light is moved away from the sensor, the voltage increases.
    2. Use an incandescent light for inspection. Bring it about 30 cm (11.8 in.) from the automatic light control sensor.



 NG
REPLACE AUTOMATIC LIGHT CONTROL SENSOR
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY


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