Lexus NX: Room Temperature Sensor Circuit (B1411)

DESCRIPTION

The cooler thermistor (room temperature sensor) is installed in the instrument panel to detect the cabin temperature which is used to control the heater and air conditioning system AUTO mode. The resistance of the cooler thermistor (room temperature sensor) changes in accordance with the cabin temperature. As the temperature decreases, the resistance increases. As the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies a voltage (5 V) to the cooler thermistor (room temperature sensor) and reads voltage changes due to changes in the resistance of the cooler thermistor (room temperature sensor).

DTC No.

Detection Item

DTC Detection Condition

Trouble Area

Memory

Note

B1411

Room Temperature Sensor Circuit

Open or short in cooler thermistor (room temperature sensor) circuit

  • Cooler thermistor (room temperature sensor)
  • Harness or connector
  • Air conditioning amplifier assembly

Memorized (4 seconds or more)

-

HINT:

  • The air conditioning amplifier assembly stores the DTC of the respective malfunction if it has occurred for the period of time indicated in the brackets.
  • If the cabin temperature is approximately -18.6°C (-1.48°F) or less, DTC B1411 may be output even though the system is normal.

WIRING DIAGRAM

CAUTION / NOTICE / HINT

NOTICE:

When the auxiliary battery is disconnected or the air conditioning amplifier assembly is replaced, be sure to perform servo motor initialization.

Click here

PROCEDURE

1.

READ VALUE USING TECHSTREAM

(a) Connect the Techstream to the DLC3.

(b) Turn the power switch on (IG).

(c) Turn the Techstream on.

(d) Enter the following menus: Body Electrical / Air Conditioner / Data List.

(e) Check the value(s) by referring to the table below.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Room Temperature Sensor

Cooler thermistor (room temperature sensor)

Min.: -6.50°C (-20.30°F)

Max.: 57.25°C (135.05°F)

Actual ambient temperature displayed

-

Body Electrical > Air Conditioner > Data List

Tester Display

Room Temperature Sensor

OK:

The display is as specified in the normal condition column.

Result

Proceed to

OK (When troubleshooting according to Problem Symptoms Table)

A

OK (When troubleshooting according to the DTC)

B

NG

C

A

PROCEED TO NEXT SUSPECTED AREA SHOWN IN PROBLEM SYMPTOMS TABLE

B

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

C

2.

INSPECT COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)

(a) Remove the cooler thermistor (room temperature sensor).

Click here

(b) Inspect the cooler thermistor (room temperature sensor).

Click here

NG

REPLACE COOLER THERMISTOR (ROOM TEMPERATURE SENSOR)

OK

3.

CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - COOLER THERMISTOR [ROOM TEMPERATURE SENSOR])

(a) Disconnect the I50 air conditioning amplifier assembly connector.

(b) Disconnect the I12 cooler thermistor (room temperature sensor) connector.

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

Standard Resistance:

Tester Connection

Condition

Specified Condition

I50-29 (TR) - I12-1

Always

Below 1 Ω

I50-34 (SG-1) - I12-2

Always

Below 1 Ω

I50-29 (TR) or I12-1 - Body ground

Always

10 kΩ or higher

I50-34 (SG-1) or I12-2 - Body ground

Always

10 kΩ or higher

OK

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

NG

REPAIR OR REPLACE HARNESS OR CONNECTOR

READ NEXT:

 Ambient Temperature Sensor Circuit (B1412)

DESCRIPTION The thermistor assembly (ambient temperature sensor) is installed in front of the cooler condenser assembly to detect the ambient temperature which is used to control the air conditioning

 Evaporator Temperature Circuit or Evaporator Fin Thermistor (B1413)

DESCRIPTION The No. 1 cooler thermistor (evaporator temperature sensor) is installed on the evaporator in the air conditioner unit to detect the temperature of the air that has passed through the evap

 Open in Pressure Sensor Circuit / Abnormal Refrigerant Pressure (B1423)

DESCRIPTION This DTC is stored if refrigerant pressure on the high pressure side is extremely low (176 kPa (1.8 kgf/cm2, 26 psi) or less) or extremely high (3025 kPa (30.8 kgf/cm2, 439 psi) or more).

SEE MORE:

 Back Camera Initialization Incomplete (C1691)

DESCRIPTION This DTC is stored when the rear television camera assembly judges that the back camera initial setting has not been memorized (rear television camera assembly optical axis adjustment (back camera position setting) is incomplete). DTC No. Detection Item DTC Detection Condition T

 Voltage Inverter

ComponentsCOMPONENTS ILLUSTRATION *1 DECK BOARD ASSEMBLY *2 DECK FLOOR BOX LH *3 NO. 2 DECK BOARD SUB-ASSEMBLY *4 NO. 3 DECK BOARD SUB-ASSEMBLY *5 REAR DECK FLOOR BOX - - ILLUSTRATION *1 DECK FLOOR BOX RH *2 NO. 1 TOOL BOX SUB-ASSEMBLY *3 NO. 2 TOOL

© 2016-2024 Copyright www.lexunx.com