Last Modified: 4-30-2014 6.6 C Doc ID: RM0000018N5001X
Model Year: 2006 Model: LX470 Prod Date Range: [05/2005 -           ]
Title: AIR CONDITIONING: AIR CONDITIONING SYSTEM: 31,41; Air Mix Damper Position Sensor Circuit; 2006 MY LX470 [05/2005 -        ]

DTC

31

Air Mix Damper Position Sensor Circuit

DTC

41

Air Mix Damper Control Servo Motor Circuit (Passenger Side)

DESCRIPTION

This sensor detects the position of the front air mix damper and sends the appropriate signals to the A/C amplifier.

The position sensor is built into the front air mix servo motor.

DTC No.

Detection Item

Trouble Area

31

Short to ground or to power source circuit in front air mix damper position sensor circuit
  • Front air mix damper position sensor
  • Harness or connector between front air mix damper position sensor and A/C amplifier
  • A/C amplifier

41

Front air mix damper position sensor value does not change even if A/C amplifier operates front air mix damper control servo motor

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK AIR CONDITIONING AMPLIFIER

(a) Remove the A/C amplifier with connectors still connected.

(b) Turn the ignition switch ON.

(c) Change the set temperature to activate the front air mix servo motor, and measure the voltage between terminals FRTP (A47-5) and FRSG (A47-18) of A/C amplifier connector every time the set temperature is changed.

Standard voltage:

Set Temperature

Specified condition

Max. cool

3.5 to 4.5 V

Max. hot

0.5 to 1.5 V

HINT:

  • As the set temperature increases, the voltage decreases.
  • However, if DTC 31 or 41 is displayed, check and replace A/C amplifier.
OK

REPLACE AIR CONDITIONING AMPLIFIER

NG

2.

CHECK FRONT AIR MIX DAMPER POSITION SENSOR

(a) Remove the front air mix servo motor.

(b) Measure the resistance between terminals 4 (PT) and 6 (GND) of the front air mix damper control servo motor connector.

Standard resistance:

4.2 to 7.8 kΩ

(c) While operating the front air mix servo motor, measure the resistance between terminals 4 and 6 of the front air mix damper control servo motor connector.

Standard resistance:

Position

Specified condition

Max. COOL

3.6 to 6.8 kΩ

Max. WARM

0.5 to 1.1 kΩ

HINT:

As the front air mix servo motor moves from the cool side to warm side, the resistance decreases.
NG

REPLACE FRONT AIR MIX SERVO MOTOR

OK

3.

CHECK WIRE HARNESS (FRONT AIR MIX DAMPER POSITION SENSOR - AIR CONDITIONING AMPLIFIER)
NG

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE AIR CONDITIONING AMPLIFIER