B1431

AIR CONDITIONING: AIR CONDITIONING SYSTEM: B1431/31: Air Mix Damper Position Sensor Circuit (Passenger Side)

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

DESCRIPTION

This sensor detects the position of the air mix damper servo and sends appropriate signals to the A/C amplifier. The position sensor is built into the air mix damper servo.

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1. READ VALUE USING TECHSTREAM (AIR MIX DAMPER POSITION SENSOR)
(a) Check the Data List for proper functioning of the air mix damper position sensor.

Air Conditioner

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

Result

C -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
2. CHECK AIR CONDITIONING AMPLIFIER ASSEMBLY (TPPa - SG-4 VOLTAGE)

(a) Remove the A/C amplifier but do not disconnect the connectors.
(b) Turn the ignition switch ON.
(c) Measure the voltage of the connectors.
Standard voltage:

HINT: As the temperature increases, the voltage decreases.

Result

C -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY
B -- PROCEED TO NEXT CIRCUIT INSPECTION SHOWN IN PROBLEM SYMPTOMS TABLE
A -- Continue to next step.
3. INSPECT AIR MIX DAMPER SERVO SUB-ASSEMBLY

(a) Remove the damper servo.
(b) Measure the resistance of the damper servo.
Standard resistance:

HINT:
- B1441 for operation procedures for the air mix damper servo.
- As the air mix damper servo moves from the cool side to warm side, the resistance decreases gradually without interruption.

NG -- REPLACE AIR MIX DAMPER SERVO SUB-ASSEMBLY
OK -- Continue to next step.
4. CHECK WIRE HARNESS (AIR MIX DAMPER SERVO - A/C AMPLIFIER)

(a) Disconnect the A18 servo connector.
(b) Disconnect the A8 and A9 amplifier connectors.
(c) Measure the resistance of the wire harness side connectors.
Standard resistance:

NG -- REPAIR OR REPLACE HARNESS OR CONNECTOR
OK -- REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY