B1431/31
Diagnostic trouble codes
DESCRIPTION
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. |
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WIRING DIAGRAM
INSPECTION PROCEDURE
| 1. READ VALUE OF INTELLIGENT TESTER |
Connect the intelligent tester to the DLC3.
Turn the ignition switch ON and push the intelligent tester main switch on.
Select the item below in the DATA LIST, and read the display on the intelligent tester.
| 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% |
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| 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
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| A | |
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| 2. INSPECT AIR CONDITIONING AMPLIFIER ASSEMBLY |
Remove the A/C amplifier assembly with the connectors still connected.
Change the set temperature to activate the air mix servomotor.
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
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| A | |
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| 3. INSPECT AIR MIX CONTROL SERVOMOTOR |
Remove the air mix control servomotor.
Disconnect the connector from the air mix control servomotor.
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
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
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).
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| OK | |
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| 4. CHECK HARNESS AND CONNECTOR (AIR MIX CONTROL SERVOMOTOR - A/C AMPLIFIER ASSEMBLY) |
Disconnect the connector from the A/C amplifier assembly.
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
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| OK | ||
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