Last Modified: 7-3-2017 6.8:8.0.40 Doc ID: RM0000018NE004X
Model Year Start: 2007 Model: LX470 Prod Date Range: [08/2006 -           ]
Title: AIR CONDITIONING: AIR CONDITIONING SYSTEM: 37,47; Rear Air Mix Damper Position Sensor Circuit; 2007 MY LX470 [08/2006 -        ]

DTC

37

Rear Air Mix Damper Position Sensor Circuit

DTC

47

Rear Air Mix Damper Control Servo Motor Circuit

DESCRIPTION

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

The position sensor is built into the rear air mix damper control servo motor.

DTC No.

Detection Item

Trouble Area

37

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

47

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

WIRING DIAGRAM

INSPECTION PROCEDURE

PROCEDURE

1.

CHECK AIR CONDITIONING AMPLIFIER

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

(b) Turn the ignition switch ON.

(c) Change the set temperature to activate the rear air mix servo motor, and measure the voltage between terminals TPH (A33-6) and SG (A33-9) of the rear A/C amplifier connector each time when 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 37 or 47 is displayed, check and replace the rear A/C amplifier.
OK

REPLACE REAR AIR CONDITIONING AMPLIFIER

NG

2.

CHECK REAR AIR MIX DAMPER POSITION SENSOR

(a) Remove the rear air mix servo motor.

(b) Measure the resistance between terminals 3 and 4 of the rear air mix damper control servo motor connector.

Standard resistance:

4.2 to 7.8 kΩ

(c) While operating the rear air mix damper control servo motor, measure the resistance between terminals 3 (PT) and 4 (GND) of the rear air mix 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 rear air mix servo motor moves from cool side to warm side, the resistance decreases.
NG

REPLACE REAR AIR MIX SERVO MOTOR ASSEMBLY

OK

3.

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

REPAIR OR REPLACE HARNESS AND CONNECTOR

OK

REPLACE REAR AIR CONDITIONING AMPLIFIER