DTC    B1431/31    Air Mix Damper Position Sensor Circuit (Passenger Side)

for Preparation Click here


DESCRIPTION

E109300E01
This sensor detects the position of the air mix control servomotor (air mix damper) and sends the appropriate signals to the A/C amplifier assembly. The position sensor is built in the air mix control servomotor arm moves.
It outputs voltage (5 V) that is input to terminal 1 (VZ) and terminal 3 (PT) via the variable resistor, and then to the A/C amplifier assembly.
The A/C amplifier assembly reads the arm position with the input voltage from the position sensor.

DTC No.
DTC Detecting Condition
Trouble Area
B1431/31
Open or short in power source circuit in air mix damper position sensor circuit.
  1. Air mix control servomotor (air mix damper position sensor)
  2. Harness and connector between air mix control servomotor and A/C amplifier assembly
  3. A/C amplifier assembly

WIRING DIAGRAM


I036321E09


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
(Range)
Normal Condition
Diagnostic Note
A/M DAMP POS-P
Air mix damper position (Passenger side) / min.: -14% max.: 113.5%
Damper is at "MAX. COOL": -5%
Damper is at "MAX. HOT": 105%
-
A/M DAMP TARG-P
Air mix damper target position (Passenger side) / min.: -14% max.: 113.5%

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 AIR CONDITIONING AMPLIFIER ASSEMBLY


    E109265E26

  1. Remove the A/C amplifier assembly with the connectors still connected.

  1. Change the set temperature to activate the air mix servomotor.

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

    Voltage:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    A10-10 (TPP) - A10-19 (SG-2)
    		Ignition switch ON
    MAX.HOT position
    		0.82 to 0.88 V
    A10-10 (TPP) - A10-19 (SG-2)
    		Ignition switch ON
    MAX.COOL position
    		4.12 to 4.18 V
    A10-22 (S5-2) - A10-19 (SG-2)
    		Ignition switch ON
    		4.5 to 5.5 V
    A10-22 (S5-2) - A10-19 (SG-2)
    		Ignition switch OFF
    		Below 1 V

    HINT:
    As the set temperature increases, the voltage decreases gradually without interruption.


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


3.INSPECT AIR MIX CONTROL SERVOMOTOR


    E110733E01

  1. Remove the air mix control servomotor.

  1. Disconnect the connector from the air mix control servomotor.

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

    Resistance:
    Tester connection
    (Symbols)
    		Condition
    		Specified condition
    A21-1 (VZ) - A21-2 (GND)
    		Always
    		4.2 to 7.8 kΩ

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

    Resistance:
    Tester connection
    		Condition
    		Specified condition
    A21-3 (PT) - A21-2 (GND)
    		MAX. COOL position
    		3.5 to 6.5 kΩ
    A21-3 (PT) - A21-2 (GND)
    		MAX. HOT position
    		0.7 to 1.3 kΩ



    E108925E03

  1. As the air mix control servomotor is moved from cool side to hot side, the resistance decreases gradually without interruption.

    HINT:
    For details regarding operation of the servomotor (Click here).



NG
REPLACE AIR MIX CONTROL SERVOMOTOR
OK


4.CHECK HARNESS AND CONNECTOR (AIR MIX CONTROL SERVOMOTOR - A/C AMPLIFIER ASSEMBLY)


    E109216E21

  1. 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
    A10-10 (TPP) - A21-3 (PT)
    		Always
    		Below 1 Ω
    A10-19 (SG-2) - A21-2 (GND)
    		Always
    		Below 1 Ω
    A10-22 (S5-2) - A21-1 (VZ)
    		Always
    		Below 1 Ω
    A10-10 (TPP) - Body ground
    		Always
    		10 kΩ or higher
    A10-19 (SG-2) - Body ground
    		Always
    		10 kΩ or higher
    A10-22 (S5-2) - Body ground
    		Always
    		10 kΩ or higher



NG
REPAIR OR REPLACE HARNESS OR CONNECTOR
OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY