HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): B1412; Ambient Temperature Sensor Circuit; 2019 MY RAV4 HV [11/2018

Last Modified: 01-30-2024	6.11:8.1.0	Doc ID: RM100000001FPGZ
Model Year Start: 2019	Model: RAV4 HV	Prod Date Range: [11/2018 - 02/2019]
Title: HEATING / AIR CONDITIONING: AIR CONDITIONING SYSTEM (for HV Model): B1412; Ambient Temperature Sensor Circuit; 2019 MY RAV4 HV [11/2018 - 02/2019]

DTC

B1412

Ambient Temperature Sensor Circuit

DESCRIPTION

The thermistor assembly is installed in front of the cooler condenser assembly to detect the ambient temperature, which is used to control the air conditioning system AUTO mode. This sensor is connected to the air conditioning amplifier assembly and detects fluctuations in the ambient temperature. This data is used for controlling the cabin temperature. The sensor sends a signal to the air conditioning amplifier assembly. The resistance of the thermistor assembly changes in accordance with the ambient temperature. As the temperature decreases, the resistance increases. Conversely, as the temperature increases, the resistance decreases.

The air conditioning amplifier assembly applies a voltage (3.3 V) to the thermistor assembly and reads voltage changes due to changes in the resistance of the thermistor assembly (ambient temperature sensor).

DTC No.	Detection Item	DTC Detection Condition	Trouble Area	Memory
B1412	Ambient Temperature Sensor Circuit	Diagnosis condition: None Malfunction status: Open or short in ambient temperature sensor circuit Detection time: None (Present malfunction), continuously for 4 seconds or more (Past malfunction)	Thermistor assembly Harness or connector Air conditioning amplifier assembly	Memorized

HINT:

If the ambient temperature is approximately -52.9°C (-63.22°F) or lower, DTC B1412 may be output even though the system is normal.

WIRING DIAGRAM

PROCEDURE

1.	READ VALUE USING TECHSTREAM (AMBIENT TEMP SENSOR)

(a) Connect the Techstream to the DLC3.

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

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

(e) Read the Data List according to the display on the Techstream.

Body Electrical > Air Conditioner > Data List

Tester Display

Measurement Item

Range

Normal Condition

Diagnostic Note

Ambient Temp Sensor

Thermistor assembly

Min.: -23.30°C (-9.94°F)

Max.: 65.95°C (150.71°F)

Actual ambient temperature displayed

Thermistor assembly system malfunction

When open circuit: -23.30°C (-9.94°F)
When short circuit: 65.95°C (150.71°F)

Body Electrical > Air Conditioner > Data List

Tester Display
Ambient Temp Sensor

OK:

The display is as specified in the normal condition column.

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

2.	INSPECT THERMISTOR ASSEMBLY

(a) Remove the thermistor assembly.

Click here

(b) Inspect the thermistor assembly.

Click here

REPLACE THERMISTOR ASSEMBLY

3.	CHECK HARNESS AND CONNECTOR (AIR CONDITIONING AMPLIFIER ASSEMBLY - THERMISTOR ASSEMBLY)

(a) Disconnect the G47 air conditioning amplifier assembly connector.

(b) Disconnect the A19 thermistor assembly connector.

Standard Resistance:

Tester Connection	Condition	Specified Condition
G47-1 (TAM) - A19-2	Always	Below 1 Ω
G47-14 (SG-2) - A19-1	Always	Below 1 Ω
G47-1 (TAM) or A19-2 - Other terminals and body ground	Always	10 kΩ or higher
G47-14 (SG-2) or A19-1 - Other terminals and body ground	Always	10 kΩ or higher

REPLACE AIR CONDITIONING AMPLIFIER ASSEMBLY

REPAIR OR REPLACE HARNESS OR CONNECTOR